chore: prepare tokio-util 0.6.6 (#3696)

Simply exposes the number of available permits of the semaphore.

This makes some kinds of bookkeeping easier without having to manually keep counts using atomics.

Fixes #2642

.cirrus.yml

@@ -1,17 +1,17 @@
 freebsd_instance:
-  image: freebsd-12-1-release-amd64
+  image: freebsd-12-2-release-amd64
 
 # Test FreeBSD in a full VM on cirrus-ci.com.  Test the i686 target too, in the
 # same VM.  The binary will be built in 32-bit mode, but will execute on a
 # 64-bit kernel and in a 64-bit environment.  Our tests don't execute any of
 # the system's binaries, so the environment shouldn't matter.
 task:
-  name: FreeBSD 12.0
+  name: FreeBSD
   env:
     LOOM_MAX_PREEMPTIONS: 2
     RUSTFLAGS: -Dwarnings
   setup_script:
-    - pkg install -y curl
+    - pkg install -y bash curl
     - curl https://sh.rustup.rs -sSf --output rustup.sh
     - sh rustup.sh -y --profile minimal --default-toolchain stable
     - . $HOME/.cargo/env
@@ -21,10 +21,9 @@ task:
       rustc --version
   test_script:
     - . $HOME/.cargo/env
-    - cargo test --all
+    - cargo test --all --all-features
     - cargo doc --all --no-deps
-  # TODO: Re-enable
-  # i686_test_script:
-  #   - . $HOME/.cargo/env
-  #   - |
-  #     cargo test --all --exclude tokio-macros --target i686-unknown-freebsd
+  i686_test_script:
+    - . $HOME/.cargo/env
+    - |
+      cargo test --all --all-features --target i686-unknown-freebsd

.github/ISSUE_TEMPLATE/bug_report.md

@@ -9,12 +9,7 @@ assignees: ''
 
 **Version**
 List the versions of all `tokio` crates you are using. The easiest way to get
-this information is using `cargo-tree`.
-
-`cargo install cargo-tree`
-(see install here: https://github.com/sfackler/cargo-tree)
-
-Then:
+this information is using `cargo tree` subcommand:
 
 `cargo tree | grep tokio`
 

.github/workflows/bench.yml

@@ -0,0 +1,55 @@
+name: Benchmark
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  benchmark:
+    name: Benchmark
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        bench:
+          - rt_multi_threaded
+          - sync_mpsc
+          - sync_rwlock
+          - sync_semaphore
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install Rust
+        run: rustup update stable
+
+      # Run benchmark with `go test -bench` and stores the output to a file
+      - name: Run benchmark
+        run: cargo bench --bench ${{ matrix.bench }} | tee ../output.txt
+        working-directory: benches
+
+      # Download previous benchmark result from cache (if exists)
+      - name: Download previous benchmark data
+        uses: actions/cache@v1
+        with:
+          path: ./cache
+          key: ${{ runner.os }}-benchmark
+
+      # Run `github-action-benchmark` action
+      - name: Store benchmark result
+        uses: rhysd/github-action-benchmark@v1
+        with:
+          name: ${{ matrix.bench }}
+          # What benchmark tool the output.txt came from
+          tool: 'cargo'
+          # Where the output from the benchmark tool is stored
+          output-file-path: output.txt
+          # # Where the previous data file is stored
+          # external-data-json-path: ./cache/benchmark-data.json
+          # Workflow will fail when an alert happens
+          fail-on-alert: true
+          # GitHub API token to make a commit comment
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          # Enable alert commit comment
+          comment-on-alert: true
+          alert-comment-cc-users: '@tokio-rs/maintainers'
+          auto-push: true
+
+      # Upload the updated cache file for the next job by actions/cache

.github/workflows/ci.yml

@@ -1,8 +1,8 @@
 on:
   push:
-    branches: ["master"]
+    branches: ["master", "tokio-*.x"]
   pull_request:
-    branches: ["master"]
+    branches: ["master", "tokio-*.x"]
 
 name: CI
 
@@ -28,6 +28,7 @@ jobs:
       - clippy
       - docs
       - loom
+      - valgrind
     steps:
       - run: exit 0
 
@@ -53,11 +54,6 @@ jobs:
         run: cargo test --features full
         working-directory: tokio
 
-      # Check `tokio` with `full + parking_lot` to make sure it compiles.
-      - name: check tokio full,parking_lot
-        run: cargo check --features full,parking_lot
-        working-directory: tokio
-
       # Test **all** crates in the workspace with all features.
       - name: test all --all-features
         run: cargo test --workspace --all-features
@@ -72,6 +68,37 @@ jobs:
         run: cargo hack test --each-feature
         working-directory: tests-build
 
+  valgrind:
+    name: valgrind
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install Rust
+        run: rustup update stable
+
+      - name: Install Valgrind
+        run: |
+          sudo apt-get update -y
+          sudo apt-get install -y valgrind
+
+      # Compile tests
+      - name: cargo build test-mem
+        run: cargo build --features rt-net --bin test-mem
+        working-directory: tests-integration
+
+      # Run with valgrind
+      - name: Run valgrind test-mem
+        run: valgrind  --leak-check=full --show-leak-kinds=all ./target/debug/test-mem
+
+      # Compile tests
+      - name: cargo build test-process-signal
+        run: cargo build --features rt-process-signal --bin test-process-signal
+        working-directory: tests-integration
+
+      # Run with valgrind
+      - name: Run valgrind test-process-signal
+        run: valgrind --leak-check=full --show-leak-kinds=all ./target/debug/test-process-signal
+
   test-unstable:
     name: test tokio full --unstable
     runs-on: ${{ matrix.os }}
@@ -112,6 +139,21 @@ jobs:
       - name: miri
         run: cargo miri test --features rt,rt-multi-thread,sync task
         working-directory: tokio
+  san:
+    name: san
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ env.nightly }}
+          override: true
+      - name: asan
+        run: cargo test --all-features --target x86_64-unknown-linux-gnu --lib -- --test-threads 1
+        working-directory: tokio
+        env:
+          RUSTFLAGS: -Z sanitizer=address
+          ASAN_OPTIONS: detect_leaks=0
 
   cross:
     name: cross
@@ -171,6 +213,26 @@ jobs:
       - name: "test --workspace --all-features"
         run: cargo check --workspace --all-features
 
+  minimal-versions:
+    name: minimal-versions
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ env.nightly }}
+          override: true
+      - name: Install cargo-hack
+        run: cargo install cargo-hack
+      - name: "check --all-features -Z minimal-versions"
+        run: |
+          # Remove dev-dependencies from Cargo.toml to prevent the next `cargo update`
+          # from determining minimal versions based on dev-dependencies.
+          cargo hack --remove-dev-deps --workspace
+          # Update Cargo.lock to minimal version dependencies.
+          cargo update -Z minimal-versions
+          cargo check --all-features
+
   fmt:
     name: fmt
     runs-on: ubuntu-latest
@@ -202,7 +264,7 @@ jobs:
 
       # Run clippy
       - name: "clippy --all"
-        run: cargo clippy --all --tests
+        run: cargo clippy --all --tests --all-features
 
   docs:
     name: docs
@@ -230,6 +292,7 @@ jobs:
           - loom_pool::group_b
           - loom_pool::group_c
           - loom_pool::group_d
+          - time::driver
     steps:
       - uses: actions/checkout@v2
       - name: Install Rust

.github/workflows/stress-test.yml

@@ -0,0 +1,32 @@
+name: Stress Test
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+
+jobs:
+  stess-test:
+    name: Stress Test
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        stress-test:
+          - simple_echo_tcp
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install Rust
+        run: rustup update stable
+
+      - name: Install Valgrind
+        run: |
+          sudo apt-get update -y
+          sudo apt-get install -y valgrind
+
+      # Compiles each of the stress test examples.
+      - name: Compile stress test examples
+        run: cargo build -p stress-test --release --example ${{ matrix.stress-test }}
+
+      # Runs each of the examples using Valgrind. Detects leaks and displays them.
+      - name: Run valgrind
+        run: valgrind  --leak-check=full --show-leak-kinds=all ./target/release/examples/${{ matrix.stress-test }}

CONTRIBUTING.md

@@ -124,17 +124,27 @@ arguments to many common cargo commands. This section lists some commonly needed
 commands.
 
 Some commands just need the `--all-features` argument:
+
 ```
 cargo build --all-features
 cargo check --all-features
 cargo test --all-features
 ```
+
 When building documentation normally, the markers that list the features
 required for various parts of Tokio are missing. To build the documentation
 correctly, use this command:
+
 ```
 RUSTDOCFLAGS="--cfg docsrs" cargo +nightly doc --all-features
 ```
+
+There is currently a [bug in cargo] that means documentation cannot be built
+from the root of the workspace. If you `cd` into the `tokio` subdirectory the
+command shown above will work.
+
+[bug in cargo]: https://github.com/rust-lang/cargo/issues/9274
+
 The `cargo fmt` command does not work on the Tokio codebase. You can use the
 command below instead:
 
@@ -427,11 +437,14 @@ _Adapted from the [Node.js contributing guide][node]_.
 
 ## Keeping track of issues and PRs
 
-The Tokio GitHub repository has a lot of issues and PRs, which is not easy to
-keep track of. This section explains the meaning of various labels, as well as
-our [GitHub project][project]. The section is primarily targeted at maintainers.
+The Tokio GitHub repository has a lot of issues and PRs to keep track of. This
+section explains the meaning of various labels, as well as our [GitHub
+project][project]. The section is primarily targeted at maintainers.  Most
+contributors aren't able to set these labels.
 
-**Area.** The area label describes the crates relevant to this issue or PR.
+### Area
+
+The area label describes the crates relevant to this issue or PR.
 
  - **A-tokio** This issue concerns the main Tokio crate.
  - **A-tokio-util** This issue concerns the `tokio-util` crate.
@@ -442,7 +455,7 @@ our [GitHub project][project]. The section is primarily targeted at maintainers.
    be used for the procedural macros, and not `join!` or `select!`.
  - **A-ci** This issue concerns our GitHub Actions setup.
 
-**Category.** The category label describes the category.
+### Category
 
  - **C-bug** This is a bug-report. Bug-fix PRs use `C-enhancement` instead.
  - **C-enhancement** This is a PR that adds a new features.
@@ -460,8 +473,7 @@ our [GitHub project][project]. The section is primarily targeted at maintainers.
  - **C-request** A non-feature request, e.g. "please add deprecation notices to
    `-alpha.*` versions of crates"
 
-**Call for participation.** I don't know why it's called `E-`. Many issues are
-missing a difficulty rating, and you should feel free to add one.
+### Calls for participation
 
  - **E-help-wanted** Stuff where we want help. Often seen together with `C-bug`
    or `C-feature-accepted`.
@@ -473,7 +485,13 @@ missing a difficulty rating, and you should feel free to add one.
  - **E-needs-mvce** This bug is missing a minimal complete and verifiable
    example.
 
-**Module.** A more fine groaned categorization than area.
+The "E-" prefix is the same as used in the Rust compiler repository. Some
+issues are missing a difficulty rating, but feel free to ask on our Discord
+server if you want to know how difficult an issue likely is.
+
+### Module
+
+The module label provides a more fine grained categorization than **Area**.
 
  - **M-blocking** Things relevant to `spawn_blocking`, `block_in_place`.
  - **M-codec** The `tokio_util::codec` module.
@@ -486,13 +504,14 @@ missing a difficulty rating, and you should feel free to add one.
  - **M-process** The `tokio::process` module.
  - **M-runtime** The `tokio::runtime` module.
  - **M-signal** The `tokio::signal` module.
- - **M-stream** The `tokio::stream` module.
  - **M-sync** The `tokio::sync` module.
  - **M-task** The `tokio::task` module.
  - **M-time** The `tokio::time` module.
  - **M-tracing** Tracing support in Tokio.
 
-**Topic.** Some extra information.
+### Topic
+
+Some extra information.
 
  - **T-docs** This is about documentation.
  - **T-performance** This is about performance.
@@ -502,6 +521,34 @@ Any label not listed here is not in active use.
 
 [project]: https://github.com/orgs/tokio-rs/projects/1
 
+## LTS guarantees
+
+Tokio ≥1.0.0 comes with LTS guarantees:
+
+ * A minimum of 5 years of maintenance.
+ * A minimum of 3 years before a hypothetical 2.0 release.
+
+The goal of these guarantees is to provide stability to the ecosystem.
+
+## Mininum Supported Rust Version (MSRV)
+
+ * All Tokio ≥1.0.0 releases will support at least a 6-month old Rust
+   compiler release.
+ * The MSRV will only be increased on 1.x releases.
+
+## Versioning Policy
+
+With Tokio ≥1.0.0:
+
+ * Patch (1.\_.x) releases _should only_ contain bug fixes or documentation
+   changes. Besides this, these releases should not substantially change
+   runtime behavior.
+ * Minor (1.x) releases may contain new functionality, MSRV increases (see
+   above), minor dependency updates, deprecations, and larger internal
+   implementation changes.
+
+This is as defined by [Semantic Versioning 2.0](https://semver.org/).
+
 ## Releasing
 
 Since the Tokio project consists of a number of crates, many of which depend on
@@ -534,9 +581,8 @@ When releasing a new version of a crate, follow these steps:
 2. **Update Cargo metadata.** After releasing any path dependencies, update the
    `version` field in `Cargo.toml` to the new version, and the `documentation`
    field to the docs.rs URL of the new version.
-3. **Update other documentation links.** Update the `#![doc(html_root_url)]`
-   attribute in the crate's `lib.rs` and the "Documentation" link in the crate's
-   `README.md` to point to the docs.rs URL of the new version.
+3. **Update other documentation links.** Update the "Documentation" link in the
+   crate's `README.md` to point to the docs.rs URL of the new version.
 4. **Update the changelog for the crate.** Each crate in the Tokio repository
    has its own `CHANGELOG.md` in that crate's subdirectory. Any changes to that
    crate since the last release should be added to the changelog. Change

Cargo.toml

@@ -4,11 +4,13 @@ members = [
   "tokio",
   "tokio-macros",
   "tokio-test",
+  "tokio-stream",
   "tokio-util",
 
   # Internal
   "benches",
   "examples",
+  "stress-test",
   "tests-build",
   "tests-integration",
 ]

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2019 Tokio Contributors
+Copyright (c) 2021 Tokio Contributors
 
 Permission is hereby granted, free of charge, to any
 person obtaining a copy of this software and associated

README.md

@@ -14,22 +14,21 @@ the Rust programming language. It is:
 
 [![Crates.io][crates-badge]][crates-url]
 [![MIT licensed][mit-badge]][mit-url]
-[![Build Status][azure-badge]][azure-url]
+[![Build Status][actions-badge]][actions-url]
 [![Discord chat][discord-badge]][discord-url]
 
 [crates-badge]: https://img.shields.io/crates/v/tokio.svg
 [crates-url]: https://crates.io/crates/tokio
 [mit-badge]: https://img.shields.io/badge/license-MIT-blue.svg
 [mit-url]: https://github.com/tokio-rs/tokio/blob/master/LICENSE
-[azure-badge]: https://dev.azure.com/tokio-rs/Tokio/_apis/build/status/tokio-rs.tokio?branchName=master
-[azure-url]: https://dev.azure.com/tokio-rs/Tokio/_build/latest?definitionId=1&branchName=master
+[actions-badge]: https://github.com/tokio-rs/tokio/workflows/CI/badge.svg
+[actions-url]: https://github.com/tokio-rs/tokio/actions?query=workflow%3ACI+branch%3Amaster
 [discord-badge]: https://img.shields.io/discord/500028886025895936.svg?logo=discord&style=flat-square
 [discord-url]: https://discord.gg/tokio
 
 [Website](https://tokio.rs) |
 [Guides](https://tokio.rs/tokio/tutorial) |
 [API Docs](https://docs.rs/tokio/latest/tokio) |
-[Roadmap](https://github.com/tokio-rs/tokio/blob/master/ROADMAP.md) |
 [Chat](https://discord.gg/tokio)
 
 ## Overview
@@ -51,11 +50,19 @@ an asynchronous application.
 
 ## Example
 
-A basic TCP echo server with Tokio:
+A basic TCP echo server with Tokio.
+
+Make sure you activated the full features of the tokio crate on Cargo.toml:
+
+```text
+[dependencies]
+tokio = { version = "1.4.0", features = ["full"] }
+```
+Then, on your main.rs:
 
 ```rust,no_run
 use tokio::net::TcpListener;
-use tokio::prelude::*;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
@@ -157,7 +164,7 @@ several other libraries, including:
 
 ## Supported Rust Versions
 
-Tokio is built against the latest stable release. The minimum supported version is 1.39.
+Tokio is built against the latest stable release. The minimum supported version is 1.45.
 The current Tokio version is not guaranteed to build on Rust versions earlier than the
 minimum supported version.
 

ROADMAP.md

@@ -1,67 +0,0 @@
-# Tokio Roadmap
-
-## A Roadmap to 1.0
-
-The question of "why not 1.0?" has come up a few times. After all, Tokio 0.1 has
-been stable for three years. The short answer: because it isn't time. There is
-nobody who would rather ship a Tokio 1.0 than us. It also isn't something to rush.
-
-After all, `async / await` only landed in the stable Rust channel weeks ago.
-There has been no significant production validation yet, except maybe fuchsia
-and that seems like a fairly specialized use case. This release of Tokio
-includes significant new code and new strategies with feature flags. Also, there
-are still big open questions, such as the [proposed changes][pr-1744] to
-`AsyncRead` and `AsyncWrite`.
-
-Tokio 1.0 will be released as soon as the APIs are proven to handle real-world
-production cases.
-
-### Tokio 1.0 in Q3 2020 with LTS support
-
-The Tokio 1.0 release will be **no later** than Q3 2020. It will also come with
-"long-term support" guarantees:
-
-* A minimum of 5 years of maintenance.
-* A minimum of 3 years before a hypothetical 2.0 release.
-
-When Tokio 1.0 is released in Q3 2020, on-going support, security fixes, and
-critical bug fixes are guaranteed until **at least** Q3 2025. Tokio 2.0 will not
-be released until **at least** Q3 2023 (though, ideally there will never be a
-Tokio 2.0 release).
-
-### How to get there
-
-While Tokio 0.1 probably should have been a 1.0, Tokio 0.2 will be a **true**
-0.2 release. There will be breaking change releases every 2 ~ 3 months until 1.0.
-These changes will be **much** smaller than going from 0.1 -> 0.2. It is
-expected that the 1.0 release will look a lot like 0.2.
-
-### What is expected to change
-
-The biggest change will be the `AsyncRead` and `AsyncWrite` traits. Based on
-experience gained over the past 3 years, there are a couple of issues to
-address:
-
-* Be able to **safely** use uninitialized memory as a read buffer.
-* Practical read vectored and write vectored APIs.
-
-There are a few strategies to solve these problems. These strategies need to be
-investigated and the solution validated. You can see [this comment][pr-1744-comment] for a
-detailed statement of the problem.
-
-The other major change, which has been in the works for a while, is updating
-Mio. Mio 0.6 was first released almost 4 years ago and has not had a breaking
-change since. Mio 0.7 has been in the works for a while. It includes a full
-rewrite of the windows support as well as a refined API. More will be written
-about this shortly.
-
-Finally, now that the API is starting to stabilize, effort will be put into
-documentation. Tokio 0.2 is being released before updating the website and many
-of the old content will no longer be relevant. In the coming weeks, expect to
-see updates there.
-
-So, we have our work cut out for us. We hope you enjoy this 0.2 release and are
-looking forward to your feedback and help.
-
-[pr-1744]: https://github.com/tokio-rs/tokio/pull/1744
-[pr-1744-comment]: https://github.com/tokio-rs/tokio/pull/1744#issuecomment-553575438

benches/Cargo.toml

@@ -5,7 +5,7 @@ publish = false
 edition = "2018"
 
 [dependencies]
-tokio = { version = "0.3.0", path = "../tokio", features = ["full"] }
+tokio = { version = "1.0.0", path = "../tokio", features = ["full"] }
 bencher = "0.1.5"
 
 [target.'cfg(unix)'.dependencies]
@@ -17,13 +17,13 @@ path = "spawn.rs"
 harness = false
 
 [[bench]]
-name = "mpsc"
-path = "mpsc.rs"
+name = "sync_mpsc"
+path = "sync_mpsc.rs"
 harness = false
 
 [[bench]]
-name = "scheduler"
-path = "scheduler.rs"
+name = "rt_multi_threaded"
+path = "rt_multi_threaded.rs"
 harness = false
 
 

benches/sync_mpsc.rs

@@ -30,22 +30,26 @@ fn create_100_000_medium(b: &mut Bencher) {
 }
 
 fn send_medium(b: &mut Bencher) {
+    let rt = rt();
+
     b.iter(|| {
         let (tx, mut rx) = mpsc::channel::<Medium>(1000);
 
-        let _ = tx.try_send([0; 64]);
+        let _ = rt.block_on(tx.send([0; 64]));
 
-        rx.try_recv().unwrap();
+        rt.block_on(rx.recv()).unwrap();
     });
 }
 
 fn send_large(b: &mut Bencher) {
+    let rt = rt();
+
     b.iter(|| {
         let (tx, mut rx) = mpsc::channel::<Large>(1000);
 
-        let _ = tx.try_send([[0; 64]; 64]);
+        let _ = rt.block_on(tx.send([[0; 64]; 64]));
 
-        rx.try_recv().unwrap();
+        rt.block_on(rx.recv()).unwrap();
     });
 }
 

examples/Cargo.toml

@@ -7,18 +7,22 @@ edition = "2018"
 # If you copy one of the examples into a new project, you should be using
 # [dependencies] instead.
 [dev-dependencies]
-tokio = { version = "0.3.0", path = "../tokio", features = ["full", "tracing"] }
+tokio = { version = "1.0.0", features = ["full", "tracing"] }
+tokio-util = { version = "0.6.3", features = ["full"] }
+tokio-stream = { version = "0.1" }
+
 tracing = "0.1"
 tracing-subscriber = { version = "0.2.7", default-features = false, features = ["fmt", "ansi", "env-filter", "chrono", "tracing-log"] }
-tokio-util = { version = "0.4.0", path = "../tokio-util", features = ["full"] }
-bytes = "0.5"
-futures = "0.3.0"
+bytes = "1.0.0"
+futures = { version = "0.3.0", features = ["thread-pool"]}
 http = "0.2"
 serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
 httparse = "1.0"
 time = "0.1"
+once_cell = "1.5.2"
+
 
 [[example]]
 name = "chat"
@@ -63,3 +67,12 @@ path = "udp-codec.rs"
 [[example]]
 name = "tinyhttp"
 path = "tinyhttp.rs"
+
+[[example]]
+name = "custom-executor"
+path = "custom-executor.rs"
+
+
+[[example]]
+name = "custom-executor-tokio-context"
+path = "custom-executor-tokio-context.rs"

examples/chat.rs

@@ -27,9 +27,9 @@
 #![warn(rust_2018_idioms)]
 
 use tokio::net::{TcpListener, TcpStream};
-use tokio::stream::{Stream, StreamExt};
 use tokio::sync::{mpsc, Mutex};
-use tokio_util::codec::{Framed, LinesCodec, LinesCodecError};
+use tokio_stream::StreamExt;
+use tokio_util::codec::{Framed, LinesCodec};
 
 use futures::SinkExt;
 use std::collections::HashMap;
@@ -37,9 +37,7 @@ use std::env;
 use std::error::Error;
 use std::io;
 use std::net::SocketAddr;
-use std::pin::Pin;
 use std::sync::Arc;
-use std::task::{Context, Poll};
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn Error>> {
@@ -168,43 +166,6 @@ impl Peer {
     }
 }
 
-#[derive(Debug)]
-enum Message {
-    /// A message that should be broadcasted to others.
-    Broadcast(String),
-
-    /// A message that should be received by a client
-    Received(String),
-}
-
-// Peer implements `Stream` in a way that polls both the `Rx`, and `Framed` types.
-// A message is produced whenever an event is ready until the `Framed` stream returns `None`.
-impl Stream for Peer {
-    type Item = Result<Message, LinesCodecError>;
-
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        // First poll the `UnboundedReceiver`.
-
-        if let Poll::Ready(Some(v)) = Pin::new(&mut self.rx).poll_next(cx) {
-            return Poll::Ready(Some(Ok(Message::Received(v))));
-        }
-
-        // Secondly poll the `Framed` stream.
-        let result: Option<_> = futures::ready!(Pin::new(&mut self.lines).poll_next(cx));
-
-        Poll::Ready(match result {
-            // We've received a message we should broadcast to others.
-            Some(Ok(message)) => Some(Ok(Message::Broadcast(message))),
-
-            // An error occurred.
-            Some(Err(e)) => Some(Err(e)),
-
-            // The stream has been exhausted.
-            None => None,
-        })
-    }
-}
-
 /// Process an individual chat client
 async fn process(
     state: Arc<Mutex<Shared>>,
@@ -238,28 +199,32 @@ async fn process(
     }
 
     // Process incoming messages until our stream is exhausted by a disconnect.
-    while let Some(result) = peer.next().await {
-        match result {
-            // A message was received from the current user, we should
-            // broadcast this message to the other users.
-            Ok(Message::Broadcast(msg)) => {
-                let mut state = state.lock().await;
-                let msg = format!("{}: {}", username, msg);
-
-                state.broadcast(addr, &msg).await;
-            }
-            // A message was received from a peer. Send it to the
-            // current user.
-            Ok(Message::Received(msg)) => {
+    loop {
+        tokio::select! {
+            // A message was received from a peer. Send it to the current user.
+            Some(msg) = peer.rx.recv() => {
                 peer.lines.send(&msg).await?;
             }
-            Err(e) => {
-                tracing::error!(
-                    "an error occurred while processing messages for {}; error = {:?}",
-                    username,
-                    e
-                );
-            }
+            result = peer.lines.next() => match result {
+                // A message was received from the current user, we should
+                // broadcast this message to the other users.
+                Some(Ok(msg)) => {
+                    let mut state = state.lock().await;
+                    let msg = format!("{}: {}", username, msg);
+
+                    state.broadcast(addr, &msg).await;
+                }
+                // An error occurred.
+                Some(Err(e)) => {
+                    tracing::error!(
+                        "an error occurred while processing messages for {}; error = {:?}",
+                        username,
+                        e
+                    );
+                }
+                // The stream has been exhausted.
+                None => break,
+            },
         }
     }
 

examples/connect.rs

@@ -92,7 +92,7 @@ mod tcp {
 
 mod udp {
     use bytes::Bytes;
-    use futures::{future, Sink, SinkExt, Stream, StreamExt};
+    use futures::{Sink, SinkExt, Stream, StreamExt};
     use std::error::Error;
     use std::io;
     use std::net::SocketAddr;
@@ -114,7 +114,7 @@ mod udp {
         let socket = UdpSocket::bind(&bind_addr).await?;
         socket.connect(addr).await?;
 
-        future::try_join(send(stdin, &socket), recv(stdout, &socket)).await?;
+        tokio::try_join!(send(stdin, &socket), recv(stdout, &socket))?;
 
         Ok(())
     }

examples/custom-executor-tokio-context.rs

@@ -0,0 +1,32 @@
+// This example shows how to use the tokio runtime with any other executor
+//
+//It takes advantage from RuntimeExt which provides the extension to customize your
+//runtime.
+
+use tokio::net::TcpListener;
+use tokio::runtime::Builder;
+use tokio::sync::oneshot;
+use tokio_util::context::RuntimeExt;
+
+fn main() {
+    let (tx, rx) = oneshot::channel();
+    let rt1 = Builder::new_multi_thread()
+        .worker_threads(1)
+        // no timer!
+        .build()
+        .unwrap();
+    let rt2 = Builder::new_multi_thread()
+        .worker_threads(1)
+        .enable_all()
+        .build()
+        .unwrap();
+
+    // Without the `HandleExt.wrap()` there would be a panic because there is
+    // no timer running, since it would be referencing runtime r1.
+    let _ = rt1.block_on(rt2.wrap(async move {
+        let listener = TcpListener::bind("0.0.0.0:0").await.unwrap();
+        println!("addr: {:?}", listener.local_addr());
+        tx.send(()).unwrap();
+    }));
+    futures::executor::block_on(rx).unwrap();
+}

examples/custom-executor.rs

@@ -0,0 +1,56 @@
+// This example shows how to use the tokio runtime with any other executor
+//
+// The main components are a spawn fn that will wrap futures in a special future
+// that will always enter the tokio context on poll. This only spawns one extra thread
+// to manage and run the tokio drivers in the background.
+
+use tokio::net::TcpListener;
+use tokio::sync::oneshot;
+
+fn main() {
+    let (tx, rx) = oneshot::channel();
+
+    my_custom_runtime::spawn(async move {
+        let listener = TcpListener::bind("0.0.0.0:0").await.unwrap();
+
+        println!("addr: {:?}", listener.local_addr());
+
+        tx.send(()).unwrap();
+    });
+
+    futures::executor::block_on(rx).unwrap();
+}
+
+mod my_custom_runtime {
+    use once_cell::sync::Lazy;
+    use std::future::Future;
+    use tokio_util::context::TokioContext;
+
+    pub fn spawn(f: impl Future<Output = ()> + Send + 'static) {
+        EXECUTOR.spawn(f);
+    }
+
+    struct ThreadPool {
+        inner: futures::executor::ThreadPool,
+        rt: tokio::runtime::Runtime,
+    }
+
+    static EXECUTOR: Lazy<ThreadPool> = Lazy::new(|| {
+        // Spawn tokio runtime on a single background thread
+        // enabling IO and timers.
+        let rt = tokio::runtime::Builder::new_multi_thread()
+            .enable_all()
+            .build()
+            .unwrap();
+        let inner = futures::executor::ThreadPool::builder().create().unwrap();
+
+        ThreadPool { inner, rt }
+    });
+
+    impl ThreadPool {
+        fn spawn(&self, f: impl Future<Output = ()> + Send + 'static) {
+            let handle = self.rt.handle().clone();
+            self.inner.spawn_ok(TokioContext::new(f, handle));
+        }
+    }
+}

examples/echo.rs

@@ -55,7 +55,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
         // which will allow all of our clients to be processed concurrently.
 
         tokio::spawn(async move {
-            let mut buf = [0; 1024];
+            let mut buf = vec![0; 1024];
 
             // In a loop, read data from the socket and write the data back.
             loop {

examples/print_each_packet.rs

@@ -55,7 +55,7 @@
 #![warn(rust_2018_idioms)]
 
 use tokio::net::TcpListener;
-use tokio::stream::StreamExt;
+use tokio_stream::StreamExt;
 use tokio_util::codec::{BytesCodec, Decoder};
 
 use std::env;

examples/proxy.rs

@@ -26,7 +26,6 @@ use tokio::io;
 use tokio::io::AsyncWriteExt;
 use tokio::net::{TcpListener, TcpStream};
 
-use futures::future::try_join;
 use futures::FutureExt;
 use std::env;
 use std::error::Error;
@@ -74,7 +73,7 @@ async fn transfer(mut inbound: TcpStream, proxy_addr: String) -> Result<(), Box<
         wi.shutdown().await
     };
 
-    try_join(client_to_server, server_to_client).await?;
+    tokio::try_join!(client_to_server, server_to_client)?;
 
     Ok(())
 }

examples/tinydb.rs

@@ -42,7 +42,7 @@
 #![warn(rust_2018_idioms)]
 
 use tokio::net::TcpListener;
-use tokio::stream::StreamExt;
+use tokio_stream::StreamExt;
 use tokio_util::codec::{Framed, LinesCodec};
 
 use futures::SinkExt;

examples/tinyhttp.rs

@@ -20,7 +20,7 @@ use http::{header::HeaderValue, Request, Response, StatusCode};
 extern crate serde_derive;
 use std::{env, error::Error, fmt, io};
 use tokio::net::{TcpListener, TcpStream};
-use tokio::stream::StreamExt;
+use tokio_stream::StreamExt;
 use tokio_util::codec::{Decoder, Encoder, Framed};
 
 #[tokio::main]

examples/udp-codec.rs

@@ -1,8 +1,3 @@
-fn main() {}
-
-// Disabled while future of UdpFramed is decided on.
-// See https://github.com/tokio-rs/tokio/issues/2830
-/*
 //! This example leverages `BytesCodec` to create a UDP client and server which
 //! speak a custom protocol.
 //!
@@ -14,8 +9,8 @@ fn main() {}
 #![warn(rust_2018_idioms)]
 
 use tokio::net::UdpSocket;
-use tokio::stream::StreamExt;
 use tokio::{io, time};
+use tokio_stream::StreamExt;
 use tokio_util::codec::BytesCodec;
 use tokio_util::udp::UdpFramed;
 
@@ -50,7 +45,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
     let b = pong(&mut b);
 
     // Run both futures simultaneously of `a` and `b` sending messages back and forth.
-    match futures::future::try_join(a, b).await {
+    match tokio::try_join!(a, b) {
         Err(e) => println!("an error occurred; error = {:?}", e),
         _ => println!("done!"),
     }
@@ -83,4 +78,3 @@ async fn pong(socket: &mut UdpFramed<BytesCodec>) -> Result<(), io::Error> {
 
     Ok(())
 }
-*/

stress-test/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "stress-test"
+version = "0.1.0"
+authors = ["Tokio Contributors <[email protected]>"]
+edition = "2018"
+publish = false
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+tokio = { path = "../tokio/", features = ["full"] }
+
+[dev-dependencies]
+rand = "0.8"

stress-test/examples/simple_echo_tcp.rs

@@ -0,0 +1,58 @@
+//! Simple TCP echo server to check memory leaks using Valgrind.
+use std::{thread::sleep, time::Duration};
+
+use tokio::{
+    io::{AsyncReadExt, AsyncWriteExt},
+    net::{TcpListener, TcpSocket},
+    runtime::Builder,
+    sync::oneshot,
+};
+
+const TCP_ENDPOINT: &str = "127.0.0.1:8080";
+const NUM_MSGS: usize = 100;
+const MSG_SIZE: usize = 1024;
+
+fn main() {
+    let rt = Builder::new_multi_thread().enable_io().build().unwrap();
+    let rt2 = Builder::new_multi_thread().enable_io().build().unwrap();
+
+    rt.spawn(async {
+        let listener = TcpListener::bind(TCP_ENDPOINT).await.unwrap();
+        let (mut socket, _) = listener.accept().await.unwrap();
+        let (mut rd, mut wr) = socket.split();
+        while tokio::io::copy(&mut rd, &mut wr).await.is_ok() {}
+    });
+
+    // wait a bit so that the listener binds.
+    sleep(Duration::from_millis(100));
+
+    // create a channel to let the main thread know that all the messages were sent and received.
+    let (tx, mut rx) = oneshot::channel();
+
+    rt2.spawn(async {
+        let addr = TCP_ENDPOINT.parse().unwrap();
+        let socket = TcpSocket::new_v4().unwrap();
+        let mut stream = socket.connect(addr).await.unwrap();
+
+        let mut buff = [0; MSG_SIZE];
+        for _ in 0..NUM_MSGS {
+            let one_mega_random_bytes: Vec<u8> =
+                (0..MSG_SIZE).map(|_| rand::random::<u8>()).collect();
+            stream
+                .write_all(one_mega_random_bytes.as_slice())
+                .await
+                .unwrap();
+            stream.read(&mut buff).await.unwrap();
+        }
+        tx.send(()).unwrap();
+    });
+
+    loop {
+        // check that we're done.
+        match rx.try_recv() {
+            Err(oneshot::error::TryRecvError::Empty) => (),
+            Err(oneshot::error::TryRecvError::Closed) => panic!("channel got closed..."),
+            Ok(()) => break,
+        }
+    }
+}

tests-build/tests/fail/macros_invalid_input.rs

@@ -12,12 +12,27 @@ async fn main_attr_has_path_args() {}
 #[tokio::test]
 fn test_is_not_async() {}
 
-#[tokio::test]
-async fn test_fn_has_args(_x: u8) {}
-
 #[tokio::test(foo)]
 async fn test_attr_has_args() {}
 
+#[tokio::test(foo = 123)]
+async fn test_unexpected_attr() {}
+
+#[tokio::test(flavor = 123)]
+async fn test_flavor_not_string() {}
+
+#[tokio::test(flavor = "foo")]
+async fn test_unknown_flavor() {}
+
+#[tokio::test(flavor = "multi_thread", start_paused = false)]
+async fn test_multi_thread_with_start_paused() {}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = "foo")]
+async fn test_worker_threads_not_int() {}
+
+#[tokio::test(flavor = "current_thread", worker_threads = 4)]
+async fn test_worker_threads_and_current_thread() {}
+
 #[tokio::test]
 #[test]
 async fn test_has_second_test_attr() {}

tests-build/tests/fail/macros_invalid_input.stderr

@@ -1,10 +1,10 @@
-error: the async keyword is missing from the function declaration
+error: the `async` keyword is missing from the function declaration
  --> $DIR/macros_invalid_input.rs:4:1
   |
 4 | fn main_is_not_async() {}
   | ^^
 
-error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`
  --> $DIR/macros_invalid_input.rs:6:15
   |
 6 | #[tokio::main(foo)]
@@ -16,26 +16,56 @@ error: Must have specified ident
 9 | #[tokio::main(threadpool::bar)]
   |               ^^^^^^^^^^^^^^^
 
-error: the async keyword is missing from the function declaration
+error: the `async` keyword is missing from the function declaration
   --> $DIR/macros_invalid_input.rs:13:1
    |
 13 | fn test_is_not_async() {}
    | ^^
 
-error: the test function cannot accept arguments
-  --> $DIR/macros_invalid_input.rs:16:27
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`
+  --> $DIR/macros_invalid_input.rs:15:15
    |
-16 | async fn test_fn_has_args(_x: u8) {}
-   |                           ^^^^^^
-
-error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`
-  --> $DIR/macros_invalid_input.rs:18:15
-   |
-18 | #[tokio::test(foo)]
+15 | #[tokio::test(foo)]
    |               ^^^
 
-error: second test attribute is supplied
-  --> $DIR/macros_invalid_input.rs:22:1
+error: Unknown attribute foo is specified; expected one of: `flavor`, `worker_threads`, `start_paused`
+  --> $DIR/macros_invalid_input.rs:18:15
    |
-22 | #[test]
+18 | #[tokio::test(foo = 123)]
+   |               ^^^^^^^^^
+
+error: Failed to parse value of `flavor` as string.
+  --> $DIR/macros_invalid_input.rs:21:24
+   |
+21 | #[tokio::test(flavor = 123)]
+   |                        ^^^
+
+error: No such runtime flavor `foo`. The runtime flavors are `current_thread` and `multi_thread`.
+  --> $DIR/macros_invalid_input.rs:24:24
+   |
+24 | #[tokio::test(flavor = "foo")]
+   |                        ^^^^^
+
+error: The `start_paused` option requires the `current_thread` runtime flavor. Use `#[tokio::test(flavor = "current_thread")]`
+  --> $DIR/macros_invalid_input.rs:27:55
+   |
+27 | #[tokio::test(flavor = "multi_thread", start_paused = false)]
+   |                                                       ^^^^^
+
+error: Failed to parse value of `worker_threads` as integer.
+  --> $DIR/macros_invalid_input.rs:30:57
+   |
+30 | #[tokio::test(flavor = "multi_thread", worker_threads = "foo")]
+   |                                                         ^^^^^
+
+error: The `worker_threads` option requires the `multi_thread` runtime flavor. Use `#[tokio::test(flavor = "multi_thread")]`
+  --> $DIR/macros_invalid_input.rs:33:59
+   |
+33 | #[tokio::test(flavor = "current_thread", worker_threads = 4)]
+   |                                                           ^
+
+error: second test attribute is supplied
+  --> $DIR/macros_invalid_input.rs:37:1
+   |
+37 | #[test]
    | ^^^^^^^

tests-build/tests/macros.rs

@@ -2,6 +2,9 @@
 fn compile_fail_full() {
     let t = trybuild::TestCases::new();
 
+    #[cfg(feature = "full")]
+    t.pass("tests/pass/forward_args_and_output.rs");
+
     #[cfg(feature = "full")]
     t.compile_fail("tests/fail/macros_invalid_input.rs");
 

tests-build/tests/pass/forward_args_and_output.rs

@@ -0,0 +1,13 @@
+use tests_build::tokio;
+
+fn main() {}
+
+// arguments and output type is forwarded so other macros can access them
+
+#[tokio::test]
+async fn test_fn_has_args(_x: u8) {}
+
+#[tokio::test]
+async fn test_has_output() -> Result<(), Box<dyn std::error::Error>> {
+    Ok(())
+}

tests-integration/Cargo.toml

@@ -5,7 +5,23 @@ authors = ["Tokio Contributors <[email protected]>"]
 edition = "2018"
 publish = false
 
+[[bin]]
+name = "test-cat"
+
+[[bin]]
+name = "test-mem"
+required-features = ["rt-net"]
+
+[[bin]]
+name = "test-process-signal"
+required-features = ["rt-process-signal"]
+
 [features]
+# For mem check
+rt-net = ["tokio/rt", "tokio/rt-multi-thread", "tokio/net"]
+# For test-process-signal
+rt-process-signal = ["rt", "tokio/process", "tokio/signal"]
+
 full = [
     "macros",
     "rt",
@@ -23,6 +39,4 @@ rt-multi-thread = ["rt", "tokio/rt-multi-thread"]
 tokio = { path = "../tokio" }
 tokio-test = { path = "../tokio-test", optional = true }
 doc-comment = "0.3.1"
-
-[dev-dependencies]
 futures = { version = "0.3.0", features = ["async-await"] }

tests-integration/src/bin/test-mem.rs

@@ -0,0 +1,21 @@
+use futures::future::poll_fn;
+
+fn main() {
+    let rt = tokio::runtime::Builder::new_multi_thread()
+        .worker_threads(1)
+        .enable_io()
+        .build()
+        .unwrap();
+
+    rt.block_on(async {
+        let listener = tokio::net::TcpListener::bind("0.0.0.0:0").await.unwrap();
+        tokio::spawn(async move {
+            loop {
+                poll_fn(|cx| listener.poll_accept(cx)).await.unwrap();
+            }
+        });
+    });
+
+    std::thread::sleep(std::time::Duration::from_millis(50));
+    drop(rt);
+}

tests-integration/src/bin/test-process-signal.rs

@@ -0,0 +1,11 @@
+// https://github.com/tokio-rs/tokio/issues/3550
+fn main() {
+    for _ in 0..1000 {
+        let rt = tokio::runtime::Builder::new_current_thread()
+            .enable_all()
+            .build()
+            .unwrap();
+
+        drop(rt);
+    }
+}

tests-integration/tests/process_stdio.rs

@@ -1,26 +1,19 @@
 #![warn(rust_2018_idioms)]
 #![cfg(feature = "full")]
 
-use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
+use tokio::io::{AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader};
+use tokio::join;
 use tokio::process::{Child, Command};
 use tokio_test::assert_ok;
 
 use futures::future::{self, FutureExt};
+use std::convert::TryInto;
 use std::env;
 use std::io;
 use std::process::{ExitStatus, Stdio};
 
 fn cat() -> Command {
-    let mut me = env::current_exe().unwrap();
-    me.pop();
-
-    if me.ends_with("deps") {
-        me.pop();
-    }
-
-    me.push("test-cat");
-
-    let mut cmd = Command::new(me);
+    let mut cmd = Command::new(env!("CARGO_BIN_EXE_test-cat"));
     cmd.stdin(Stdio::piped()).stdout(Stdio::piped());
     cmd
 }
@@ -148,3 +141,52 @@ async fn try_wait() {
     // Can't get id after process has exited
     assert_eq!(child.id(), None);
 }
+
+#[tokio::test]
+async fn pipe_from_one_command_to_another() {
+    let mut first = cat().spawn().expect("first cmd");
+    let mut third = cat().spawn().expect("third cmd");
+
+    // Convert ChildStdout to Stdio
+    let second_stdin: Stdio = first
+        .stdout
+        .take()
+        .expect("first.stdout")
+        .try_into()
+        .expect("first.stdout into Stdio");
+
+    // Convert ChildStdin to Stdio
+    let second_stdout: Stdio = third
+        .stdin
+        .take()
+        .expect("third.stdin")
+        .try_into()
+        .expect("third.stdin into Stdio");
+
+    let mut second = cat()
+        .stdin(second_stdin)
+        .stdout(second_stdout)
+        .spawn()
+        .expect("first cmd");
+
+    let msg = "hello world! please pipe this message through";
+
+    let mut stdin = first.stdin.take().expect("first.stdin");
+    let write = async move { stdin.write_all(msg.as_bytes()).await };
+
+    let mut stdout = third.stdout.take().expect("third.stdout");
+    let read = async move {
+        let mut data = String::new();
+        stdout.read_to_string(&mut data).await.map(|_| data)
+    };
+
+    let (read, write, first_status, second_status, third_status) =
+        join!(read, write, first.wait(), second.wait(), third.wait());
+
+    assert_eq!(msg, read.expect("read result"));
+    write.expect("write result");
+
+    assert!(first_status.expect("first status").success());
+    assert!(second_status.expect("second status").success());
+    assert!(third_status.expect("third status").success());
+}

tokio-macros/CHANGELOG.md

@@ -1,3 +1,17 @@
+# 1.1.0 (February 5, 2021)
+
+- add `start_paused` option to macros ([#3492])
+
+# 1.0.0 (December 23, 2020)
+
+- track `tokio` 1.0 release.
+
+# 0.3.1 (October 25, 2020)
+
+### Fixed
+
+- fix incorrect docs regarding `max_threads` option ([#3038])
+
 # 0.3.0 (October 15, 2020)
 
 - Track `tokio` 0.3 release.
@@ -38,9 +52,11 @@
 
 - Initial release
 
-[#2225]: https://github.com/tokio-rs/tokio/pull/2225
-[#2177]: https://github.com/tokio-rs/tokio/pull/2177
-[#2152]: https://github.com/tokio-rs/tokio/pull/2152
-[#2038]: https://github.com/tokio-rs/tokio/pull/2038
-[#2022]: https://github.com/tokio-rs/tokio/pull/2022
 [#1954]: https://github.com/tokio-rs/tokio/pull/1954
+[#2022]: https://github.com/tokio-rs/tokio/pull/2022
+[#2038]: https://github.com/tokio-rs/tokio/pull/2038
+[#2152]: https://github.com/tokio-rs/tokio/pull/2152
+[#2177]: https://github.com/tokio-rs/tokio/pull/2177
+[#2225]: https://github.com/tokio-rs/tokio/pull/2225
+[#3038]: https://github.com/tokio-rs/tokio/pull/3038
+[#3492]: https://github.com/tokio-rs/tokio/pull/3492

tokio-macros/Cargo.toml

@@ -2,23 +2,21 @@
 name = "tokio-macros"
 # When releasing to crates.io:
 # - Remove path dependencies
-# - Update html_root_url.
 # - Update doc url
 #   - Cargo.toml
 # - Update CHANGELOG.md.
-# - Create "v0.3.x" git tag.
-version = "0.3.0"
+# - Create "tokio-macros-1.0.x" git tag.
+version = "1.1.0"
 edition = "2018"
 authors = ["Tokio Contributors <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"
 homepage = "https://tokio.rs"
-documentation = "https://docs.rs/tokio-macros/0.3.0/tokio_macros"
+documentation = "https://docs.rs/tokio-macros/1.1.0/tokio_macros"
 description = """
 Tokio's proc macros.
 """
 categories = ["asynchronous"]
-publish = false
 
 [lib]
 proc-macro = true
@@ -31,7 +29,7 @@ quote = "1"
 syn = { version = "1.0.3", features = ["full"] }
 
 [dev-dependencies]
-tokio = { version = "0.3.0", path = "../tokio", features = ["full"] }
+tokio = { version = "1.0.0", path = "../tokio", features = ["full"] }
 
 [package.metadata.docs.rs]
 all-features = true

tokio-macros/LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2019 Tokio Contributors
+Copyright (c) 2021 Tokio Contributors
 
 Permission is hereby granted, free of charge, to any
 person obtaining a copy of this software and associated

tokio-macros/src/entry.rs

@@ -1,7 +1,6 @@
 use proc_macro::TokenStream;
 use proc_macro2::Span;
 use quote::quote;
-use syn::spanned::Spanned;
 
 #[derive(Clone, Copy, PartialEq)]
 enum RuntimeFlavor {
@@ -25,6 +24,7 @@ impl RuntimeFlavor {
 struct FinalConfig {
     flavor: RuntimeFlavor,
     worker_threads: Option<usize>,
+    start_paused: Option<bool>,
 }
 
 struct Configuration {
@@ -32,6 +32,8 @@ struct Configuration {
     default_flavor: RuntimeFlavor,
     flavor: Option<RuntimeFlavor>,
     worker_threads: Option<(usize, Span)>,
+    start_paused: Option<(bool, Span)>,
+    is_test: bool,
 }
 
 impl Configuration {
@@ -44,6 +46,8 @@ impl Configuration {
             },
             flavor: None,
             worker_threads: None,
+            start_paused: None,
+            is_test,
         }
     }
 
@@ -79,31 +83,67 @@ impl Configuration {
         Ok(())
     }
 
+    fn set_start_paused(&mut self, start_paused: syn::Lit, span: Span) -> Result<(), syn::Error> {
+        if self.start_paused.is_some() {
+            return Err(syn::Error::new(span, "`start_paused` set multiple times."));
+        }
+
+        let start_paused = parse_bool(start_paused, span, "start_paused")?;
+        self.start_paused = Some((start_paused, span));
+        Ok(())
+    }
+
+    fn macro_name(&self) -> &'static str {
+        if self.is_test {
+            "tokio::test"
+        } else {
+            "tokio::main"
+        }
+    }
+
     fn build(&self) -> Result<FinalConfig, syn::Error> {
         let flavor = self.flavor.unwrap_or(self.default_flavor);
         use RuntimeFlavor::*;
-        match (flavor, self.worker_threads) {
-            (CurrentThread, Some((_, worker_threads_span))) => Err(syn::Error::new(
-                worker_threads_span,
-                "The `worker_threads` option requires the `multi_thread` runtime flavor.",
-            )),
-            (CurrentThread, None) => Ok(FinalConfig {
-                flavor,
-                worker_threads: None,
-            }),
-            (Threaded, worker_threads) if self.rt_multi_thread_available => Ok(FinalConfig {
-                flavor,
-                worker_threads: worker_threads.map(|(val, _span)| val),
-            }),
+
+        let worker_threads = match (flavor, self.worker_threads) {
+            (CurrentThread, Some((_, worker_threads_span))) => {
+                let msg = format!(
+                    "The `worker_threads` option requires the `multi_thread` runtime flavor. Use `#[{}(flavor = \"multi_thread\")]`",
+                    self.macro_name(),
+                );
+                return Err(syn::Error::new(worker_threads_span, msg));
+            }
+            (CurrentThread, None) => None,
+            (Threaded, worker_threads) if self.rt_multi_thread_available => {
+                worker_threads.map(|(val, _span)| val)
+            }
             (Threaded, _) => {
                 let msg = if self.flavor.is_none() {
                     "The default runtime flavor is `multi_thread`, but the `rt-multi-thread` feature is disabled."
                 } else {
                     "The runtime flavor `multi_thread` requires the `rt-multi-thread` feature."
                 };
-                Err(syn::Error::new(Span::call_site(), msg))
+                return Err(syn::Error::new(Span::call_site(), msg));
             }
-        }
+        };
+
+        let start_paused = match (flavor, self.start_paused) {
+            (Threaded, Some((_, start_paused_span))) => {
+                let msg = format!(
+                    "The `start_paused` option requires the `current_thread` runtime flavor. Use `#[{}(flavor = \"current_thread\")]`",
+                    self.macro_name(),
+                );
+                return Err(syn::Error::new(start_paused_span, msg));
+            }
+            (CurrentThread, Some((start_paused, _))) => Some(start_paused),
+            (_, None) => None,
+        };
+
+        Ok(FinalConfig {
+            flavor,
+            worker_threads,
+            start_paused,
+        })
     }
 }
 
@@ -113,12 +153,12 @@ fn parse_int(int: syn::Lit, span: Span, field: &str) -> Result<usize, syn::Error
             Ok(value) => Ok(value),
             Err(e) => Err(syn::Error::new(
                 span,
-                format!("Failed to parse {} as integer: {}", field, e),
+                format!("Failed to parse value of `{}` as integer: {}", field, e),
             )),
         },
         _ => Err(syn::Error::new(
             span,
-            format!("Failed to parse {} as integer.", field),
+            format!("Failed to parse value of `{}` as integer.", field),
         )),
     }
 }
@@ -129,7 +169,17 @@ fn parse_string(int: syn::Lit, span: Span, field: &str) -> Result<String, syn::E
         syn::Lit::Verbatim(s) => Ok(s.to_string()),
         _ => Err(syn::Error::new(
             span,
-            format!("Failed to parse {} as string.", field),
+            format!("Failed to parse value of `{}` as string.", field),
+        )),
+    }
+}
+
+fn parse_bool(bool: syn::Lit, span: Span, field: &str) -> Result<bool, syn::Error> {
+    match bool {
+        syn::Lit::Bool(b) => Ok(b.value),
+        _ => Err(syn::Error::new(
+            span,
+            format!("Failed to parse value of `{}` as bool.", field),
         )),
     }
 }
@@ -140,24 +190,13 @@ fn parse_knobs(
     is_test: bool,
     rt_multi_thread: bool,
 ) -> Result<TokenStream, syn::Error> {
-    let sig = &mut input.sig;
-    let body = &input.block;
-    let attrs = &input.attrs;
-    let vis = input.vis;
-
-    if sig.asyncness.is_none() {
-        let msg = "the async keyword is missing from the function declaration";
-        return Err(syn::Error::new_spanned(sig.fn_token, msg));
+    if input.sig.asyncness.take().is_none() {
+        let msg = "the `async` keyword is missing from the function declaration";
+        return Err(syn::Error::new_spanned(input.sig.fn_token, msg));
     }
 
-    sig.asyncness = None;
-
-    let macro_name = if is_test {
-        "tokio::test"
-    } else {
-        "tokio::main"
-    };
     let mut config = Configuration::new(is_test, rt_multi_thread);
+    let macro_name = config.macro_name();
 
     for arg in args {
         match arg {
@@ -169,17 +208,32 @@ fn parse_knobs(
                 }
                 match ident.unwrap().to_string().to_lowercase().as_str() {
                     "worker_threads" => {
-                        config.set_worker_threads(namevalue.lit.clone(), namevalue.span())?;
+                        config.set_worker_threads(
+                            namevalue.lit.clone(),
+                            syn::spanned::Spanned::span(&namevalue.lit),
+                        )?;
                     }
                     "flavor" => {
-                        config.set_flavor(namevalue.lit.clone(), namevalue.span())?;
+                        config.set_flavor(
+                            namevalue.lit.clone(),
+                            syn::spanned::Spanned::span(&namevalue.lit),
+                        )?;
+                    }
+                    "start_paused" => {
+                        config.set_start_paused(
+                            namevalue.lit.clone(),
+                            syn::spanned::Spanned::span(&namevalue.lit),
+                        )?;
                     }
                     "core_threads" => {
                         let msg = "Attribute `core_threads` is renamed to `worker_threads`";
                         return Err(syn::Error::new_spanned(namevalue, msg));
                     }
                     name => {
-                        let msg = format!("Unknown attribute {} is specified; expected one of: `flavor`, `worker_threads`, `max_threads`", name);
+                        let msg = format!(
+                            "Unknown attribute {} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`",
+                            name,
+                        );
                         return Err(syn::Error::new_spanned(namevalue, msg));
                     }
                 }
@@ -193,17 +247,23 @@ fn parse_knobs(
                 let name = ident.unwrap().to_string().to_lowercase();
                 let msg = match name.as_str() {
                     "threaded_scheduler" | "multi_thread" => {
-                        format!("Set the runtime flavor with #[{}(flavor = \"multi_thread\")].", macro_name)
-                    },
+                        format!(
+                            "Set the runtime flavor with #[{}(flavor = \"multi_thread\")].",
+                            macro_name
+                        )
+                    }
                     "basic_scheduler" | "current_thread" | "single_threaded" => {
-                        format!("Set the runtime flavor with #[{}(flavor = \"current_thread\")].", macro_name)
-                    },
-                    "flavor" | "worker_threads" => {
+                        format!(
+                            "Set the runtime flavor with #[{}(flavor = \"current_thread\")].",
+                            macro_name
+                        )
+                    }
+                    "flavor" | "worker_threads" | "start_paused" => {
                         format!("The `{}` attribute requires an argument.", name)
-                    },
+                    }
                     name => {
-                        format!("Unknown attribute {} is specified; expected one of: `flavor`, `worker_threads`", name)
-                    },
+                        format!("Unknown attribute {} is specified; expected one of: `flavor`, `worker_threads`, `start_paused`", name)
+                    }
                 };
                 return Err(syn::Error::new_spanned(path, msg));
             }
@@ -229,27 +289,32 @@ fn parse_knobs(
     if let Some(v) = config.worker_threads {
         rt = quote! { #rt.worker_threads(#v) };
     }
+    if let Some(v) = config.start_paused {
+        rt = quote! { #rt.start_paused(#v) };
+    }
 
-    let header = {
-        if is_test {
-            quote! {
-                #[::core::prelude::v1::test]
-            }
-        } else {
-            quote! {}
+    let header = if is_test {
+        quote! {
+            #[::core::prelude::v1::test]
+        }
+    } else {
+        quote! {}
+    };
+
+    let body = &input.block;
+    input.block = syn::parse_quote! {
+        {
+            #rt
+                .enable_all()
+                .build()
+                .unwrap()
+                .block_on(async #body)
         }
     };
 
     let result = quote! {
         #header
-        #(#attrs)*
-        #vis #sig {
-            #rt
-                .enable_all()
-                .build()
-                .unwrap()
-                .block_on(async { #body })
-        }
+        #input
     };
 
     Ok(result.into())
@@ -283,12 +348,5 @@ pub(crate) fn test(args: TokenStream, item: TokenStream, rt_multi_thread: bool)
         }
     }
 
-    if !input.sig.inputs.is_empty() {
-        let msg = "the test function cannot accept arguments";
-        return syn::Error::new_spanned(&input.sig.inputs, msg)
-            .to_compile_error()
-            .into();
-    }
-
     parse_knobs(input, args, true, rt_multi_thread).unwrap_or_else(|e| e.to_compile_error().into())
 }

tokio-macros/src/lib.rs

@@ -1,4 +1,3 @@
-#![doc(html_root_url = "https://docs.rs/tokio-macros/0.3.0")]
 #![allow(clippy::needless_doctest_main)]
 #![warn(
     missing_debug_implementations,
@@ -24,8 +23,8 @@ mod select;
 
 use proc_macro::TokenStream;
 
-/// Marks async function to be executed by the selected runtime. This macro helps
-/// set up a `Runtime` without requiring the user to use
+/// Marks async function to be executed by the selected runtime. This macro
+/// helps set up a `Runtime` without requiring the user to use
 /// [Runtime](../tokio/runtime/struct.Runtime.html) or
 /// [Builder](../tokio/runtime/struct.Builder.html) directly.
 ///
@@ -35,6 +34,12 @@ use proc_macro::TokenStream;
 /// [Builder](../tokio/runtime/struct.Builder.html), which provides a more
 /// powerful interface.
 ///
+/// Note: This macro can be used on any function and not just the `main`
+/// function. Using it on a non-main function makes the function behave as if it
+/// was synchronous by starting a new runtime each time it is called. If the
+/// function is called often, it is preferable to create the runtime using the
+/// runtime builder so the runtime can be reused across calls.
+///
 /// # Multi-threaded runtime
 ///
 /// To use the multi-threaded runtime, the macro can be configured using
@@ -47,6 +52,9 @@ use proc_macro::TokenStream;
 /// The `worker_threads` option configures the number of worker threads, and
 /// defaults to the number of cpus on the system. This is the default flavor.
 ///
+/// Note: The multi-threaded runtime requires the `rt-multi-thread` feature
+/// flag.
+///
 /// # Current thread runtime
 ///
 /// To use the single-threaded runtime known as the `current_thread` runtime,
@@ -135,12 +143,38 @@ use proc_macro::TokenStream;
 /// }
 /// ```
 ///
+/// ### Configure the runtime to start with time paused
+///
+/// ```rust
+/// #[tokio::main(flavor = "current_thread", start_paused = true)]
+/// async fn main() {
+///     println!("Hello world");
+/// }
+/// ```
+///
+/// Equivalent code not using `#[tokio::main]`
+///
+/// ```rust
+/// fn main() {
+///     tokio::runtime::Builder::new_current_thread()
+///         .enable_all()
+///         .start_paused(true)
+///         .build()
+///         .unwrap()
+///         .block_on(async {
+///             println!("Hello world");
+///         })
+/// }
+/// ```
+///
+/// Note that `start_paused` requires the `test-util` feature to be enabled.
+///
 /// ### NOTE:
 ///
-/// If you rename the tokio crate in your dependencies this macro will not work.
-/// If you must rename the 0.2 version of tokio because you're also using the
-/// 0.1 version of tokio, you _must_ make the tokio 0.2 crate available as
-/// `tokio` in the module where this macro is expanded.
+/// If you rename the Tokio crate in your dependencies this macro will not work.
+/// If you must rename the current version of Tokio because you're also using an
+/// older version of Tokio, you _must_ make the current version of Tokio
+/// available as `tokio` in the module where this macro is expanded.
 #[proc_macro_attribute]
 #[cfg(not(test))] // Work around for rust-lang/rust#62127
 pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
@@ -182,11 +216,10 @@ pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
 ///
 /// ### NOTE:
 ///
-/// If you rename the tokio crate in your dependencies this macro
-/// will not work. If you must rename the 0.2 version of tokio because
-/// you're also using the 0.1 version of tokio, you _must_ make the
-/// tokio 0.2 crate available as `tokio` in the module where this
-/// macro is expanded.
+/// If you rename the Tokio crate in your dependencies this macro will not work.
+/// If you must rename the current version of Tokio because you're also using an
+/// older version of Tokio, you _must_ make the current version of Tokio
+/// available as `tokio` in the module where this macro is expanded.
 #[proc_macro_attribute]
 #[cfg(not(test))] // Work around for rust-lang/rust#62127
 pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
@@ -208,7 +241,7 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 ///
 /// ### Using default
 ///
-/// The default test runtime is multi-threaded.
+/// The default test runtime is single-threaded.
 ///
 /// ```no_run
 /// #[tokio::test]
@@ -217,13 +250,23 @@ pub fn main_rt(args: TokenStream, item: TokenStream) -> TokenStream {
 /// }
 /// ```
 ///
+/// ### Configure the runtime to start with time paused
+///
+/// ```no_run
+/// #[tokio::test(start_paused = true)]
+/// async fn my_test() {
+///     assert!(true);
+/// }
+/// ```
+///
+/// Note that `start_paused` requires the `test-util` feature to be enabled.
+///
 /// ### NOTE:
 ///
-/// If you rename the tokio crate in your dependencies this macro
-/// will not work. If you must rename the 0.2 version of tokio because
-/// you're also using the 0.1 version of tokio, you _must_ make the
-/// tokio 0.2 crate available as `tokio` in the module where this
-/// macro is expanded.
+/// If you rename the Tokio crate in your dependencies this macro will not work.
+/// If you must rename the current version of Tokio because you're also using an
+/// older version of Tokio, you _must_ make the current version of Tokio
+/// available as `tokio` in the module where this macro is expanded.
 #[proc_macro_attribute]
 pub fn test(args: TokenStream, item: TokenStream) -> TokenStream {
     entry::test(args, item, true)
@@ -231,10 +274,6 @@ pub fn test(args: TokenStream, item: TokenStream) -> TokenStream {
 
 /// Marks async function to be executed by runtime, suitable to test environment
 ///
-/// ## Options:
-///
-/// - `max_threads=n` - Sets max threads to `n`.
-///
 /// ## Usage
 ///
 /// ```no_run
@@ -246,11 +285,10 @@ pub fn test(args: TokenStream, item: TokenStream) -> TokenStream {
 ///
 /// ### NOTE:
 ///
-/// If you rename the tokio crate in your dependencies this macro
-/// will not work. If you must rename the 0.2 version of tokio because
-/// you're also using the 0.1 version of tokio, you _must_ make the
-/// tokio 0.2 crate available as `tokio` in the module where this
-/// macro is expanded.
+/// If you rename the Tokio crate in your dependencies this macro will not work.
+/// If you must rename the current version of Tokio because you're also using an
+/// older version of Tokio, you _must_ make the current version of Tokio
+/// available as `tokio` in the module where this macro is expanded.
 #[proc_macro_attribute]
 pub fn test_rt(args: TokenStream, item: TokenStream) -> TokenStream {
     entry::test(args, item, false)

tokio-stream/CHANGELOG.md

@@ -0,0 +1,56 @@
+# 0.1.5 (March 20, 2021)
+
+### Fixed
+
+- stream: documentation note for throttle `Unpin` ([#3600])
+
+[#3600]: https://github.com/tokio-rs/tokio/pull/3600
+
+# 0.1.4 (March 9, 2021)
+
+Added
+
+- signal: add `Signal` wrapper ([#3510])
+
+Fixed
+
+- stream: remove duplicate `doc_cfg` declaration ([#3561])
+- sync: yield initial value in `WatchStream` ([#3576])
+
+[#3510]: https://github.com/tokio-rs/tokio/pull/3510
+[#3561]: https://github.com/tokio-rs/tokio/pull/3561
+[#3576]: https://github.com/tokio-rs/tokio/pull/3576
+
+# 0.1.3 (February 5, 2021)
+
+Added
+
+ - sync: add wrapper for broadcast and watch ([#3384], [#3504])
+
+[#3384]: https://github.com/tokio-rs/tokio/pull/3384
+[#3504]: https://github.com/tokio-rs/tokio/pull/3504
+
+# 0.1.2 (January 12, 2021)
+
+Fixed
+
+ - docs: fix some wrappers missing in documentation ([#3378])
+
+[#3378]: https://github.com/tokio-rs/tokio/pull/3378
+
+# 0.1.1 (January 4, 2021)
+
+Added
+
+ - add `Stream` wrappers ([#3343])
+
+Fixed
+
+ - move `async-stream` to `dev-dependencies` ([#3366])
+
+[#3366]: https://github.com/tokio-rs/tokio/pull/3366
+[#3343]: https://github.com/tokio-rs/tokio/pull/3343
+
+# 0.1.0 (December 23, 2020)
+
+ - Initial release

tokio-stream/Cargo.toml

@@ -0,0 +1,46 @@
+[package]
+name = "tokio-stream"
+# When releasing to crates.io:
+# - Remove path dependencies
+# - Update doc url
+#   - Cargo.toml
+# - Update CHANGELOG.md.
+# - Create "tokio-stream-0.1.x" git tag.
+version = "0.1.5"
+edition = "2018"
+authors = ["Tokio Contributors <[email protected]>"]
+license = "MIT"
+repository = "https://github.com/tokio-rs/tokio"
+homepage = "https://tokio.rs"
+documentation = "https://docs.rs/tokio-stream/0.1.5/tokio_stream"
+description = """
+Utilities to work with `Stream` and `tokio`.
+"""
+categories = ["asynchronous"]
+
+[features]
+default = ["time"]
+time = ["tokio/time"]
+net = ["tokio/net"]
+io-util = ["tokio/io-util"]
+fs = ["tokio/fs"]
+sync = ["tokio/sync", "tokio-util"]
+signal = ["tokio/signal"]
+
+[dependencies]
+futures-core = { version = "0.3.0" }
+pin-project-lite = "0.2.0"
+tokio = { version = "1.2.0", path = "../tokio", features = ["sync"] }
+tokio-util = { version = "0.6.3", optional = true }
+
+[dev-dependencies]
+tokio = { version = "1.2.0", path = "../tokio", features = ["full", "test-util"] }
+async-stream = "0.3"
+tokio-test = { path = "../tokio-test" }
+futures = { version = "0.3", default-features = false }
+
+proptest = "1"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]

tokio-stream/LICENSE

@@ -0,0 +1,25 @@
+Copyright (c) 2021 Tokio Contributors
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

tokio-stream/src/empty.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::marker::PhantomData;
 use core::pin::Pin;
@@ -24,7 +24,7 @@ unsafe impl<T> Sync for Empty<T> {}
 /// Basic usage:
 ///
 /// ```
-/// use tokio::stream::{self, StreamExt};
+/// use tokio_stream::{self as stream, StreamExt};
 ///
 /// #[tokio::main]
 /// async fn main() {

tokio-stream/src/iter.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::pin::Pin;
 use core::task::{Context, Poll};
@@ -8,6 +8,7 @@ use core::task::{Context, Poll};
 #[must_use = "streams do nothing unless polled"]
 pub struct Iter<I> {
     iter: I,
+    yield_amt: usize,
 }
 
 impl<I> Unpin for Iter<I> {}
@@ -20,7 +21,7 @@ impl<I> Unpin for Iter<I> {}
 ///
 /// ```
 /// # async fn dox() {
-/// use tokio::stream::{self, StreamExt};
+/// use tokio_stream::{self as stream, StreamExt};
 ///
 /// let mut stream = stream::iter(vec![17, 19]);
 ///
@@ -35,6 +36,7 @@ where
 {
     Iter {
         iter: i.into_iter(),
+        yield_amt: 0,
     }
 }
 
@@ -45,9 +47,18 @@ where
     type Item = I::Item;
 
     fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<I::Item>> {
-        let coop = ready!(crate::coop::poll_proceed(cx));
-        coop.made_progress();
-        Poll::Ready(self.iter.next())
+        // TODO: add coop back
+        if self.yield_amt >= 32 {
+            self.yield_amt = 0;
+
+            cx.waker().wake_by_ref();
+
+            Poll::Pending
+        } else {
+            self.yield_amt += 1;
+
+            Poll::Ready(self.iter.next())
+        }
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {

tokio-stream/src/lib.rs

@@ -0,0 +1,98 @@
+#![allow(
+    clippy::cognitive_complexity,
+    clippy::large_enum_variant,
+    clippy::needless_doctest_main
+)]
+#![warn(
+    missing_debug_implementations,
+    missing_docs,
+    rust_2018_idioms,
+    unreachable_pub
+)]
+#![cfg_attr(docsrs, feature(doc_cfg))]
+#![cfg_attr(docsrs, deny(broken_intra_doc_links))]
+#![doc(test(
+    no_crate_inject,
+    attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
+))]
+
+//! Stream utilities for Tokio.
+//!
+//! A `Stream` is an asynchronous sequence of values. It can be thought of as
+//! an asynchronous version of the standard library's `Iterator` trait.
+//!
+//! This crate provides helpers to work with them. For examples of usage and a more in-depth
+//! description of streams you can also refer to the [streams
+//! tutorial](https://tokio.rs/tokio/tutorial/streams) on the tokio website.
+//!
+//! # Iterating over a Stream
+//!
+//! Due to similarities with the standard library's `Iterator` trait, some new
+//! users may assume that they can use `for in` syntax to iterate over a
+//! `Stream`, but this is unfortunately not possible. Instead, you can use a
+//! `while let` loop as follows:
+//!
+//! ```rust
+//! use tokio_stream::{self as stream, StreamExt};
+//!
+//! #[tokio::main]
+//! async fn main() {
+//!     let mut stream = stream::iter(vec![0, 1, 2]);
+//!
+//!     while let Some(value) = stream.next().await {
+//!         println!("Got {}", value);
+//!     }
+//! }
+//! ```
+//!
+//! # Returning a Stream from a function
+//!
+//! A common way to stream values from a function is to pass in the sender
+//! half of a channel and use the receiver as the stream. This requires awaiting
+//! both futures to ensure progress is made. Another alternative is the
+//! [async-stream] crate, which contains macros that provide a `yield` keyword
+//! and allow you to return an `impl Stream`.
+//!
+//! [async-stream]: https://docs.rs/async-stream
+//!
+//! # Conversion to and from AsyncRead/AsyncWrite
+//!
+//! It is often desirable to convert a `Stream` into an [`AsyncRead`],
+//! especially when dealing with plaintext formats streamed over the network.
+//! The opposite conversion from an [`AsyncRead`] into a `Stream` is also
+//! another commonly required feature. To enable these conversions,
+//! [`tokio-util`] provides the [`StreamReader`] and [`ReaderStream`]
+//! types when the io feature is enabled.
+//!
+//! [`tokio-util`]: https://docs.rs/tokio-util/0.4/tokio_util/codec/index.html
+//! [`tokio::io`]: https://docs.rs/tokio/1.0/tokio/io/index.html
+//! [`AsyncRead`]: https://docs.rs/tokio/1.0/tokio/io/trait.AsyncRead.html
+//! [`AsyncWrite`]: https://docs.rs/tokio/1.0/tokio/io/trait.AsyncWrite.html
+//! [`ReaderStream`]: https://docs.rs/tokio-util/0.4/tokio_util/io/struct.ReaderStream.html
+//! [`StreamReader`]: https://docs.rs/tokio-util/0.4/tokio_util/io/struct.StreamReader.html
+
+#[macro_use]
+mod macros;
+
+pub mod wrappers;
+
+mod stream_ext;
+pub use stream_ext::{collect::FromStream, StreamExt};
+
+mod empty;
+pub use empty::{empty, Empty};
+
+mod iter;
+pub use iter::{iter, Iter};
+
+mod once;
+pub use once::{once, Once};
+
+mod pending;
+pub use pending::{pending, Pending};
+
+mod stream_map;
+pub use stream_map::StreamMap;
+
+#[doc(no_inline)]
+pub use futures_core::Stream;

tokio-stream/src/macros.rs

@@ -0,0 +1,68 @@
+macro_rules! cfg_fs {
+    ($($item:item)*) => {
+        $(
+            #[cfg(feature = "fs")]
+            #[cfg_attr(docsrs, doc(cfg(feature = "fs")))]
+            $item
+        )*
+    }
+}
+
+macro_rules! cfg_io_util {
+    ($($item:item)*) => {
+        $(
+            #[cfg(feature = "io-util")]
+            #[cfg_attr(docsrs, doc(cfg(feature = "io-util")))]
+            $item
+        )*
+    }
+}
+
+macro_rules! cfg_net {
+    ($($item:item)*) => {
+        $(
+            #[cfg(feature = "net")]
+            #[cfg_attr(docsrs, doc(cfg(feature = "net")))]
+            $item
+        )*
+    }
+}
+
+macro_rules! cfg_time {
+    ($($item:item)*) => {
+        $(
+            #[cfg(feature = "time")]
+            #[cfg_attr(docsrs, doc(cfg(feature = "time")))]
+            $item
+        )*
+    }
+}
+
+macro_rules! cfg_sync {
+    ($($item:item)*) => {
+        $(
+            #[cfg(feature = "sync")]
+            #[cfg_attr(docsrs, doc(cfg(feature = "sync")))]
+            $item
+        )*
+    }
+}
+
+macro_rules! cfg_signal {
+    ($($item:item)*) => {
+        $(
+            #[cfg(feature = "signal")]
+            #[cfg_attr(docsrs, doc(cfg(feature = "signal")))]
+            $item
+        )*
+    }
+}
+
+macro_rules! ready {
+    ($e:expr $(,)?) => {
+        match $e {
+            std::task::Poll::Ready(t) => t,
+            std::task::Poll::Pending => return std::task::Poll::Pending,
+        }
+    };
+}

tokio-stream/src/once.rs

@@ -1,4 +1,4 @@
-use crate::stream::{self, Iter, Stream};
+use crate::{Iter, Stream};
 
 use core::option;
 use core::pin::Pin;
@@ -20,7 +20,7 @@ impl<I> Unpin for Once<I> {}
 /// # Examples
 ///
 /// ```
-/// use tokio::stream::{self, StreamExt};
+/// use tokio_stream::{self as stream, StreamExt};
 ///
 /// #[tokio::main]
 /// async fn main() {
@@ -35,7 +35,7 @@ impl<I> Unpin for Once<I> {}
 /// ```
 pub fn once<T>(value: T) -> Once<T> {
     Once {
-        iter: stream::iter(Some(value).into_iter()),
+        iter: crate::iter(Some(value).into_iter()),
     }
 }
 

tokio-stream/src/pending.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::marker::PhantomData;
 use core::pin::Pin;
@@ -16,7 +16,7 @@ unsafe impl<T> Sync for Pending<T> {}
 /// Creates a stream that is never ready
 ///
 /// The returned stream is never ready. Attempting to call
-/// [`next()`](crate::stream::StreamExt::next) will never complete. Use
+/// [`next()`](crate::StreamExt::next) will never complete. Use
 /// [`stream::empty()`](super::empty()) to obtain a stream that is is
 /// immediately empty but returns no values.
 ///
@@ -25,7 +25,7 @@ unsafe impl<T> Sync for Pending<T> {}
 /// Basic usage:
 ///
 /// ```no_run
-/// use tokio::stream::{self, StreamExt};
+/// use tokio_stream::{self as stream, StreamExt};
 ///
 /// #[tokio::main]
 /// async fn main() {

tokio-stream/src/stream_ext.rs

@@ -1,57 +1,4 @@
-//! Stream utilities for Tokio.
-//!
-//! A `Stream` is an asynchronous sequence of values. It can be thought of as
-//! an asynchronous version of the standard library's `Iterator` trait.
-//!
-//! This module provides helpers to work with them. For examples of usage and a more in-depth
-//! description of streams you can also refer to the [streams
-//! tutorial](https://tokio.rs/tokio/tutorial/streams) on the tokio website.
-//!
-//! # Iterating over a Stream
-//!
-//! Due to similarities with the standard library's `Iterator` trait, some new
-//! users may assume that they can use `for in` syntax to iterate over a
-//! `Stream`, but this is unfortunately not possible. Instead, you can use a
-//! `while let` loop as follows:
-//!
-//! ```rust
-//! use tokio::stream::{self, StreamExt};
-//!
-//! #[tokio::main]
-//! async fn main() {
-//!     let mut stream = stream::iter(vec![0, 1, 2]);
-//!
-//!     while let Some(value) = stream.next().await {
-//!         println!("Got {}", value);
-//!     }
-//! }
-//! ```
-//!
-//! # Returning a Stream from a function
-//!
-//! A common way to stream values from a function is to pass in the sender
-//! half of a channel and use the receiver as the stream. This requires awaiting
-//! both futures to ensure progress is made. Another alternative is the
-//! [async-stream] crate, which contains macros that provide a `yield` keyword
-//! and allow you to return an `impl Stream`.
-//!
-//! [async-stream]: https://docs.rs/async-stream
-//!
-//! # Conversion to and from AsyncRead/AsyncWrite
-//!
-//! It is often desirable to convert a `Stream` into an [`AsyncRead`],
-//! especially when dealing with plaintext formats streamed over the network.
-//! The opposite conversion from an [`AsyncRead`] into a `Stream` is also
-//! another commonly required feature. To enable these conversions,
-//! [`tokio-util`] provides the [`StreamReader`] and [`ReaderStream`]
-//! types when the io feature is enabled.
-//!
-//! [tokio-util]: https://docs.rs/tokio-util/0.3/tokio_util/codec/index.html
-//! [`tokio::io`]: crate::io
-//! [`AsyncRead`]: crate::io::AsyncRead
-//! [`AsyncWrite`]: crate::io::AsyncWrite
-//! [`ReaderStream`]: https://docs.rs/tokio-util/0.4/tokio_util/io/struct.ReaderStream.html
-//! [`StreamReader`]: https://docs.rs/tokio-util/0.4/tokio_util/io/struct.StreamReader.html
+use futures_core::Stream;
 
 mod all;
 use all::AllFuture;
@@ -62,12 +9,8 @@ use any::AnyFuture;
 mod chain;
 use chain::Chain;
 
-mod collect;
-use collect::Collect;
-pub use collect::FromStream;
-
-mod empty;
-pub use empty::{empty, Empty};
+pub(crate) mod collect;
+use collect::{Collect, FromStream};
 
 mod filter;
 use filter::Filter;
@@ -81,9 +24,6 @@ use fold::FoldFuture;
 mod fuse;
 use fuse::Fuse;
 
-mod iter;
-pub use iter::{iter, Iter};
-
 mod map;
 use map::Map;
 
@@ -93,15 +33,6 @@ use merge::Merge;
 mod next;
 use next::Next;
 
-mod once;
-pub use once::{once, Once};
-
-mod pending;
-pub use pending::{pending, Pending};
-
-mod stream_map;
-pub use stream_map::StreamMap;
-
 mod skip;
 use skip::Skip;
 
@@ -120,16 +51,44 @@ use take_while::TakeWhile;
 cfg_time! {
     mod timeout;
     use timeout::Timeout;
-    use crate::time::Duration;
+    use tokio::time::Duration;
     mod throttle;
-    use crate::stream::throttle::{throttle, Throttle};
+    use throttle::{throttle, Throttle};
 }
 
-#[doc(no_inline)]
-pub use futures_core::Stream;
-
-/// An extension trait for `Stream`s that provides a variety of convenient
-/// combinator functions.
+/// An extension trait for the [`Stream`] trait that provides a variety of
+/// convenient combinator functions.
+///
+/// Be aware that the `Stream` trait in Tokio is a re-export of the trait found
+/// in the [futures] crate, however both Tokio and futures provide separate
+/// `StreamExt` utility traits, and some utilities are only available on one of
+/// these traits. Click [here][futures-StreamExt] to see the other `StreamExt`
+/// trait in the futures crate.
+///
+/// If you need utilities from both `StreamExt` traits, you should prefer to
+/// import one of them, and use the other through the fully qualified call
+/// syntax. For example:
+/// ```
+/// // import one of the traits:
+/// use futures::stream::StreamExt;
+/// # #[tokio::main(flavor = "current_thread")]
+/// # async fn main() {
+///
+/// let a = tokio_stream::iter(vec![1, 3, 5]);
+/// let b = tokio_stream::iter(vec![2, 4, 6]);
+///
+/// // use the fully qualified call syntax for the other trait:
+/// let merged = tokio_stream::StreamExt::merge(a, b);
+///
+/// // use normal call notation for futures::stream::StreamExt::collect
+/// let output: Vec<_> = merged.collect().await;
+/// assert_eq!(output, vec![1, 2, 3, 4, 5, 6]);
+/// # }
+/// ```
+///
+/// [`Stream`]: crate::Stream
+/// [futures]: https://docs.rs/futures
+/// [futures-StreamExt]: https://docs.rs/futures/0.3/futures/stream/trait.StreamExt.html
 pub trait StreamExt: Stream {
     /// Consumes and returns the next value in the stream or `None` if the
     /// stream is finished.
@@ -152,7 +111,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let mut stream = stream::iter(1..=3);
     ///
@@ -188,7 +147,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let mut stream = stream::iter(vec![Ok(1), Ok(2), Err("nope")]);
     ///
@@ -220,7 +179,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let stream = stream::iter(1..=3);
     /// let mut stream = stream.map(|x| x + 3);
@@ -253,16 +212,17 @@ pub trait StreamExt: Stream {
     ///
     /// For merging multiple streams, consider using [`StreamMap`] instead.
     ///
-    /// [`StreamMap`]: crate::stream::StreamMap
+    /// [`StreamMap`]: crate::StreamMap
     ///
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::StreamExt;
+    /// use tokio_stream::{StreamExt, Stream};
     /// use tokio::sync::mpsc;
     /// use tokio::time;
     ///
     /// use std::time::Duration;
+    /// use std::pin::Pin;
     ///
     /// # /*
     /// #[tokio::main]
@@ -270,8 +230,21 @@ pub trait StreamExt: Stream {
     /// # #[tokio::main(flavor = "current_thread")]
     /// async fn main() {
     /// # time::pause();
-    ///     let (tx1, rx1) = mpsc::channel(10);
-    ///     let (tx2, rx2) = mpsc::channel(10);
+    ///     let (tx1, mut rx1) = mpsc::channel::<usize>(10);
+    ///     let (tx2, mut rx2) = mpsc::channel::<usize>(10);
+    ///
+    ///     // Convert the channels to a `Stream`.
+    ///     let rx1 = Box::pin(async_stream::stream! {
+    ///           while let Some(item) = rx1.recv().await {
+    ///               yield item;
+    ///           }
+    ///     }) as Pin<Box<dyn Stream<Item = usize> + Send>>;
+    ///
+    ///     let rx2 = Box::pin(async_stream::stream! {
+    ///           while let Some(item) = rx2.recv().await {
+    ///               yield item;
+    ///           }
+    ///     }) as Pin<Box<dyn Stream<Item = usize> + Send>>;
     ///
     ///     let mut rx = rx1.merge(rx2);
     ///
@@ -334,7 +307,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let stream = stream::iter(1..=8);
     /// let mut evens = stream.filter(|x| x % 2 == 0);
@@ -370,7 +343,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let stream = stream::iter(1..=8);
     /// let mut evens = stream.filter_map(|x| {
@@ -402,7 +375,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{Stream, StreamExt};
+    /// use tokio_stream::{Stream, StreamExt};
     ///
     /// use std::pin::Pin;
     /// use std::task::{Context, Poll};
@@ -467,7 +440,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let mut stream = stream::iter(1..=10).take(3);
     ///
@@ -496,7 +469,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let mut stream = stream::iter(1..=10).take_while(|x| *x <= 3);
     ///
@@ -522,7 +495,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let mut stream = stream::iter(1..=10).skip(7);
     ///
@@ -553,7 +526,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     /// let mut stream = stream::iter(vec![1,2,3,4,1]).skip_while(|x| *x < 3);
     ///
     /// assert_eq!(Some(3), stream.next().await);
@@ -596,7 +569,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let a = [1, 2, 3];
     ///
@@ -611,7 +584,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let a = [1, 2, 3];
     ///
@@ -655,7 +628,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let a = [1, 2, 3];
     ///
@@ -670,7 +643,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// let a = [1, 2, 3];
     ///
@@ -699,7 +672,7 @@ pub trait StreamExt: Stream {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// #[tokio::main]
     /// async fn main() {
@@ -739,7 +712,7 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, *};
+    /// use tokio_stream::{self as stream, *};
     ///
     /// let s = stream::iter(vec![1u8, 2, 3]);
     /// let sum = s.fold(0, |acc, x| acc + x).await;
@@ -766,7 +739,9 @@ pub trait StreamExt: Stream {
     /// `collect` streams all values, awaiting as needed. Values are pushed into
     /// a collection. A number of different target collection types are
     /// supported, including [`Vec`](std::vec::Vec),
-    /// [`String`](std::string::String), and [`Bytes`](bytes::Bytes).
+    /// [`String`](std::string::String), and [`Bytes`].
+    ///
+    /// [`Bytes`]: https://docs.rs/bytes/0.6.0/bytes/struct.Bytes.html
     ///
     /// # `Result`
     ///
@@ -785,7 +760,7 @@ pub trait StreamExt: Stream {
     /// Basic usage:
     ///
     /// ```
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// #[tokio::main]
     /// async fn main() {
@@ -802,7 +777,7 @@ pub trait StreamExt: Stream {
     /// Collecting a stream of `Result` values
     ///
     /// ```
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     ///
     /// #[tokio::main]
     /// async fn main() {
@@ -858,11 +833,12 @@ pub trait StreamExt: Stream {
     /// ```
     /// # #[tokio::main]
     /// # async fn main() {
-    /// use tokio::stream::{self, StreamExt};
+    /// use tokio_stream::{self as stream, StreamExt};
     /// use std::time::Duration;
     /// # let int_stream = stream::iter(1..=3);
     ///
-    /// let mut int_stream = int_stream.timeout(Duration::from_secs(1));
+    /// let int_stream = int_stream.timeout(Duration::from_secs(1));
+    /// tokio::pin!(int_stream);
     ///
     /// // When no items time out, we get the 3 elements in succession:
     /// assert_eq!(int_stream.try_next().await, Ok(Some(1)));
@@ -903,10 +879,11 @@ pub trait StreamExt: Stream {
     /// Create a throttled stream.
     /// ```rust,no_run
     /// use std::time::Duration;
-    /// use tokio::stream::StreamExt;
+    /// use tokio_stream::StreamExt;
     ///
     /// # async fn dox() {
-    /// let mut item_stream = futures::stream::repeat("one").throttle(Duration::from_secs(2));
+    /// let item_stream = futures::stream::repeat("one").throttle(Duration::from_secs(2));
+    /// tokio::pin!(item_stream);
     ///
     /// loop {
     ///     // The string will be produced at most every 2 seconds

tokio-stream/src/stream_ext/all.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::future::Future;
 use core::marker::PhantomPinned;
@@ -38,18 +38,21 @@ where
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let me = self.project();
-        let next = futures_core::ready!(Pin::new(me.stream).poll_next(cx));
+        let mut stream = Pin::new(me.stream);
 
-        match next {
-            Some(v) => {
-                if !(me.f)(v) {
-                    Poll::Ready(false)
-                } else {
-                    cx.waker().wake_by_ref();
-                    Poll::Pending
+        // Take a maximum of 32 items from the stream before yielding.
+        for _ in 0..32 {
+            match futures_core::ready!(stream.as_mut().poll_next(cx)) {
+                Some(v) => {
+                    if !(me.f)(v) {
+                        return Poll::Ready(false);
+                    }
                 }
+                None => return Poll::Ready(true),
             }
-            None => Poll::Ready(true),
         }
+
+        cx.waker().wake_by_ref();
+        Poll::Pending
     }
 }

tokio-stream/src/stream_ext/any.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::future::Future;
 use core::marker::PhantomPinned;
@@ -38,18 +38,21 @@ where
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let me = self.project();
-        let next = futures_core::ready!(Pin::new(me.stream).poll_next(cx));
+        let mut stream = Pin::new(me.stream);
 
-        match next {
-            Some(v) => {
-                if (me.f)(v) {
-                    Poll::Ready(true)
-                } else {
-                    cx.waker().wake_by_ref();
-                    Poll::Pending
+        // Take a maximum of 32 items from the stream before yielding.
+        for _ in 0..32 {
+            match futures_core::ready!(stream.as_mut().poll_next(cx)) {
+                Some(v) => {
+                    if (me.f)(v) {
+                        return Poll::Ready(true);
+                    }
                 }
+                None => return Poll::Ready(false),
             }
-            None => Poll::Ready(false),
         }
+
+        cx.waker().wake_by_ref();
+        Poll::Pending
     }
 }

tokio-stream/src/stream_ext/chain.rs

@@ -1,4 +1,5 @@
-use crate::stream::{Fuse, Stream};
+use crate::stream_ext::Fuse;
+use crate::Stream;
 
 use core::pin::Pin;
 use core::task::{Context, Poll};

tokio-stream/src/stream_ext/collect.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::future::Future;
 use core::marker::PhantomPinned;
@@ -26,7 +26,7 @@ pin_project! {
     }
 }
 
-/// Convert from a [`Stream`](crate::stream::Stream).
+/// Convert from a [`Stream`](crate::Stream).
 ///
 /// This trait is not intended to be used directly. Instead, call
 /// [`StreamExt::collect()`](super::StreamExt::collect).

tokio-stream/src/stream_ext/filter.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;

tokio-stream/src/stream_ext/filter_map.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;

tokio-stream/src/stream_ext/fold.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::future::Future;
 use core::marker::PhantomPinned;

tokio-stream/src/stream_ext/fuse.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use pin_project_lite::pin_project;
 use std::pin::Pin;

tokio-stream/src/stream_ext/map.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;

tokio-stream/src/stream_ext/merge.rs

@@ -1,4 +1,5 @@
-use crate::stream::{Fuse, Stream};
+use crate::stream_ext::Fuse;
+use crate::Stream;
 
 use core::pin::Pin;
 use core::task::{Context, Poll};

tokio-stream/src/stream_ext/next.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::future::Future;
 use core::marker::PhantomPinned;

tokio-stream/src/stream_ext/skip.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;

tokio-stream/src/stream_ext/skip_while.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;

tokio-stream/src/stream_ext/take.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::cmp;
 use core::fmt;

tokio-stream/src/stream_ext/take_while.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use core::fmt;
 use core::pin::Pin;

tokio-stream/src/stream_ext/throttle.rs

@@ -1,7 +1,7 @@
 //! Slow down a stream by enforcing a delay between items.
 
-use crate::stream::Stream;
-use crate::time::{Duration, Instant, Sleep};
+use crate::Stream;
+use tokio::time::{Duration, Instant, Sleep};
 
 use std::future::Future;
 use std::marker::Unpin;
@@ -14,14 +14,8 @@ pub(super) fn throttle<T>(duration: Duration, stream: T) -> Throttle<T>
 where
     T: Stream,
 {
-    let delay = if duration == Duration::from_millis(0) {
-        None
-    } else {
-        Some(Sleep::new_timeout(Instant::now() + duration, duration))
-    };
-
     Throttle {
-        delay,
+        delay: tokio::time::sleep_until(Instant::now() + duration),
         duration,
         has_delayed: true,
         stream,
@@ -29,12 +23,13 @@ where
 }
 
 pin_project! {
-    /// Stream for the [`throttle`](throttle) function.
+    /// Stream for the [`throttle`](throttle) function. This object is `!Unpin`. If you need it to
+    /// implement `Unpin` you can pin your throttle like this: `Box::pin(your_throttle)`.
     #[derive(Debug)]
     #[must_use = "streams do nothing unless polled"]
     pub struct Throttle<T> {
-        // `None` when duration is zero.
-        delay: Option<Sleep>,
+        #[pin]
+        delay: Sleep,
         duration: Duration,
 
         // Set to true when `delay` has returned ready, but `stream` hasn't.
@@ -75,23 +70,29 @@ impl<T: Unpin> Throttle<T> {
 impl<T: Stream> Stream for Throttle<T> {
     type Item = T::Item;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Option<Self::Item>> {
-        if !self.has_delayed && self.delay.is_some() {
-            ready!(Pin::new(self.as_mut().project().delay.as_mut().unwrap()).poll(cx));
-            *self.as_mut().project().has_delayed = true;
+    fn poll_next(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Option<Self::Item>> {
+        let mut me = self.project();
+        let dur = *me.duration;
+
+        if !*me.has_delayed && !is_zero(dur) {
+            ready!(me.delay.as_mut().poll(cx));
+            *me.has_delayed = true;
         }
 
-        let value = ready!(self.as_mut().project().stream.poll_next(cx));
+        let value = ready!(me.stream.poll_next(cx));
 
         if value.is_some() {
-            let dur = self.duration;
-            if let Some(ref mut delay) = self.as_mut().project().delay {
-                delay.reset(Instant::now() + dur);
+            if !is_zero(dur) {
+                me.delay.reset(Instant::now() + dur);
             }
 
-            *self.as_mut().project().has_delayed = false;
+            *me.has_delayed = false;
         }
 
         Poll::Ready(value)
     }
 }
+
+fn is_zero(dur: Duration) -> bool {
+    dur == Duration::from_millis(0)
+}

tokio-stream/src/stream_ext/timeout.rs

@@ -1,10 +1,12 @@
-use crate::stream::{Fuse, Stream};
-use crate::time::{error::Elapsed, Instant, Sleep};
+use crate::stream_ext::Fuse;
+use crate::Stream;
+use tokio::time::{Instant, Sleep};
 
 use core::future::Future;
 use core::pin::Pin;
 use core::task::{Context, Poll};
 use pin_project_lite::pin_project;
+use std::fmt;
 use std::time::Duration;
 
 pin_project! {
@@ -14,16 +16,21 @@ pin_project! {
     pub struct Timeout<S> {
         #[pin]
         stream: Fuse<S>,
+        #[pin]
         deadline: Sleep,
         duration: Duration,
         poll_deadline: bool,
     }
 }
 
+/// Error returned by `Timeout`.
+#[derive(Debug, PartialEq)]
+pub struct Elapsed(());
+
 impl<S: Stream> Timeout<S> {
     pub(super) fn new(stream: S, duration: Duration) -> Self {
         let next = Instant::now() + duration;
-        let deadline = Sleep::new_timeout(next, duration);
+        let deadline = tokio::time::sleep_until(next);
 
         Timeout {
             stream: Fuse::new(stream),
@@ -37,22 +44,24 @@ impl<S: Stream> Timeout<S> {
 impl<S: Stream> Stream for Timeout<S> {
     type Item = Result<S::Item, Elapsed>;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        match self.as_mut().project().stream.poll_next(cx) {
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let me = self.project();
+
+        match me.stream.poll_next(cx) {
             Poll::Ready(v) => {
                 if v.is_some() {
-                    let next = Instant::now() + self.duration;
-                    self.as_mut().project().deadline.reset(next);
-                    *self.as_mut().project().poll_deadline = true;
+                    let next = Instant::now() + *me.duration;
+                    me.deadline.reset(next);
+                    *me.poll_deadline = true;
                 }
                 return Poll::Ready(v.map(Ok));
             }
             Poll::Pending => {}
         };
 
-        if self.poll_deadline {
-            ready!(Pin::new(self.as_mut().project().deadline).poll(cx));
-            *self.as_mut().project().poll_deadline = false;
+        if *me.poll_deadline {
+            ready!(me.deadline.poll(cx));
+            *me.poll_deadline = false;
             return Poll::Ready(Some(Err(Elapsed::new())));
         }
 
@@ -63,3 +72,25 @@ impl<S: Stream> Stream for Timeout<S> {
         self.stream.size_hint()
     }
 }
+
+// ===== impl Elapsed =====
+
+impl Elapsed {
+    pub(crate) fn new() -> Self {
+        Elapsed(())
+    }
+}
+
+impl fmt::Display for Elapsed {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        "deadline has elapsed".fmt(fmt)
+    }
+}
+
+impl std::error::Error for Elapsed {}
+
+impl From<Elapsed> for std::io::Error {
+    fn from(_err: Elapsed) -> std::io::Error {
+        std::io::ErrorKind::TimedOut.into()
+    }
+}

tokio-stream/src/stream_ext/try_next.rs

@@ -1,4 +1,5 @@
-use crate::stream::{Next, Stream};
+use crate::stream_ext::Next;
+use crate::Stream;
 
 use core::future::Future;
 use core::marker::PhantomPinned;

tokio-stream/src/stream_map.rs

@@ -1,4 +1,4 @@
-use crate::stream::Stream;
+use crate::Stream;
 
 use std::borrow::Borrow;
 use std::hash::Hash;
@@ -42,9 +42,9 @@ use std::task::{Context, Poll};
 /// to be merged, it may be advisable to use tasks sending values on a shared
 /// [`mpsc`] channel.
 ///
-/// [`StreamExt::merge`]: crate::stream::StreamExt::merge
-/// [`mpsc`]: crate::sync::mpsc
-/// [`pin!`]: macro@pin
+/// [`StreamExt::merge`]: crate::StreamExt::merge
+/// [`mpsc`]: https://docs.rs/tokio/1.0/tokio/sync/mpsc/index.html
+/// [`pin!`]: https://docs.rs/tokio/1.0/tokio/macro.pin.html
 /// [`Box::pin`]: std::boxed::Box::pin
 ///
 /// # Examples
@@ -52,13 +52,27 @@ use std::task::{Context, Poll};
 /// Merging two streams, then remove them after receiving the first value
 ///
 /// ```
-/// use tokio::stream::{StreamExt, StreamMap};
+/// use tokio_stream::{StreamExt, StreamMap, Stream};
 /// use tokio::sync::mpsc;
+/// use std::pin::Pin;
 ///
 /// #[tokio::main]
 /// async fn main() {
-///     let (tx1, rx1) = mpsc::channel(10);
-///     let (tx2, rx2) = mpsc::channel(10);
+///     let (tx1, mut rx1) = mpsc::channel::<usize>(10);
+///     let (tx2, mut rx2) = mpsc::channel::<usize>(10);
+///
+///     // Convert the channels to a `Stream`.
+///     let rx1 = Box::pin(async_stream::stream! {
+///           while let Some(item) = rx1.recv().await {
+///               yield item;
+///           }
+///     }) as Pin<Box<dyn Stream<Item = usize> + Send>>;
+///
+///     let rx2 = Box::pin(async_stream::stream! {
+///           while let Some(item) = rx2.recv().await {
+///               yield item;
+///           }
+///     }) as Pin<Box<dyn Stream<Item = usize> + Send>>;
 ///
 ///     tokio::spawn(async move {
 ///         tx1.send(1).await.unwrap();
@@ -103,7 +117,7 @@ use std::task::{Context, Poll};
 /// sent to the client over a socket.
 ///
 /// ```no_run
-/// use tokio::stream::{Stream, StreamExt, StreamMap};
+/// use tokio_stream::{Stream, StreamExt, StreamMap};
 ///
 /// enum Command {
 ///     Join(String),
@@ -112,13 +126,13 @@ use std::task::{Context, Poll};
 ///
 /// fn commands() -> impl Stream<Item = Command> {
 ///     // Streams in user commands by parsing `stdin`.
-/// # tokio::stream::pending()
+/// # tokio_stream::pending()
 /// }
 ///
 /// // Join a channel, returns a stream of messages received on the channel.
 /// fn join(channel: &str) -> impl Stream<Item = String> + Unpin {
 ///     // left as an exercise to the reader
-/// # tokio::stream::pending()
+/// # tokio_stream::pending()
 /// }
 ///
 /// #[tokio::main]
@@ -156,7 +170,7 @@ use std::task::{Context, Poll};
 ///     }
 /// }
 /// ```
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct StreamMap<K, V> {
     /// Streams stored in the map
     entries: Vec<(K, V)>,
@@ -170,7 +184,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut map = StreamMap::new();
     ///
@@ -193,7 +207,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut map = StreamMap::new();
     ///
@@ -217,7 +231,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, Pending};
+    /// use tokio_stream::{StreamMap, Pending};
     ///
     /// let map: StreamMap<&str, Pending<()>> = StreamMap::new();
     /// ```
@@ -233,7 +247,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, Pending};
+    /// use tokio_stream::{StreamMap, Pending};
     ///
     /// let map: StreamMap<&str, Pending<()>> = StreamMap::with_capacity(10);
     /// ```
@@ -250,7 +264,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut map = StreamMap::new();
     ///
@@ -273,7 +287,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut map = StreamMap::new();
     ///
@@ -296,7 +310,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut map = StreamMap::new();
     ///
@@ -320,7 +334,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, Pending};
+    /// use tokio_stream::{StreamMap, Pending};
     ///
     /// let map: StreamMap<i32, Pending<()>> = StreamMap::with_capacity(100);
     /// assert!(map.capacity() >= 100);
@@ -334,7 +348,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut a = StreamMap::new();
     /// assert_eq!(a.len(), 0);
@@ -367,7 +381,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut a = StreamMap::new();
     /// a.insert(1, pending::<i32>());
@@ -388,7 +402,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut map = StreamMap::new();
     ///
@@ -416,7 +430,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut map = StreamMap::new();
     /// map.insert(1, pending::<i32>());
@@ -445,7 +459,7 @@ impl<K, V> StreamMap<K, V> {
     /// # Examples
     ///
     /// ```
-    /// use tokio::stream::{StreamMap, pending};
+    /// use tokio_stream::{StreamMap, pending};
     ///
     /// let mut map = StreamMap::new();
     /// map.insert(1, pending::<i32>());
@@ -476,7 +490,7 @@ where
     fn poll_next_entry(&mut self, cx: &mut Context<'_>) -> Poll<Option<(usize, V::Item)>> {
         use Poll::*;
 
-        let start = crate::util::thread_rng_n(self.entries.len() as u32) as usize;
+        let start = self::rand::thread_rng_n(self.entries.len() as u32) as usize;
         let mut idx = start;
 
         for _ in 0..self.entries.len() {
@@ -513,6 +527,12 @@ where
     }
 }
 
+impl<K, V> Default for StreamMap<K, V> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<K, V> Stream for StreamMap<K, V>
 where
     K: Clone + Unpin,
@@ -547,3 +567,98 @@ where
         ret
     }
 }
+
+mod rand {
+    use std::cell::Cell;
+
+    mod loom {
+        #[cfg(not(loom))]
+        pub(crate) mod rand {
+            use std::collections::hash_map::RandomState;
+            use std::hash::{BuildHasher, Hash, Hasher};
+            use std::sync::atomic::AtomicU32;
+            use std::sync::atomic::Ordering::Relaxed;
+
+            static COUNTER: AtomicU32 = AtomicU32::new(1);
+
+            pub(crate) fn seed() -> u64 {
+                let rand_state = RandomState::new();
+
+                let mut hasher = rand_state.build_hasher();
+
+                // Hash some unique-ish data to generate some new state
+                COUNTER.fetch_add(1, Relaxed).hash(&mut hasher);
+
+                // Get the seed
+                hasher.finish()
+            }
+        }
+
+        #[cfg(loom)]
+        pub(crate) mod rand {
+            pub(crate) fn seed() -> u64 {
+                1
+            }
+        }
+    }
+
+    /// Fast random number generate
+    ///
+    /// Implement xorshift64+: 2 32-bit xorshift sequences added together.
+    /// Shift triplet [17,7,16] was calculated as indicated in Marsaglia's
+    /// Xorshift paper: https://www.jstatsoft.org/article/view/v008i14/xorshift.pdf
+    /// This generator passes the SmallCrush suite, part of TestU01 framework:
+    /// http://simul.iro.umontreal.ca/testu01/tu01.html
+    #[derive(Debug)]
+    pub(crate) struct FastRand {
+        one: Cell<u32>,
+        two: Cell<u32>,
+    }
+
+    impl FastRand {
+        /// Initialize a new, thread-local, fast random number generator.
+        pub(crate) fn new(seed: u64) -> FastRand {
+            let one = (seed >> 32) as u32;
+            let mut two = seed as u32;
+
+            if two == 0 {
+                // This value cannot be zero
+                two = 1;
+            }
+
+            FastRand {
+                one: Cell::new(one),
+                two: Cell::new(two),
+            }
+        }
+
+        pub(crate) fn fastrand_n(&self, n: u32) -> u32 {
+            // This is similar to fastrand() % n, but faster.
+            // See https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/
+            let mul = (self.fastrand() as u64).wrapping_mul(n as u64);
+            (mul >> 32) as u32
+        }
+
+        fn fastrand(&self) -> u32 {
+            let mut s1 = self.one.get();
+            let s0 = self.two.get();
+
+            s1 ^= s1 << 17;
+            s1 = s1 ^ s0 ^ s1 >> 7 ^ s0 >> 16;
+
+            self.one.set(s0);
+            self.two.set(s1);
+
+            s0.wrapping_add(s1)
+        }
+    }
+
+    // Used by `StreamMap`
+    pub(crate) fn thread_rng_n(n: u32) -> u32 {
+        thread_local! {
+            static THREAD_RNG: FastRand = FastRand::new(loom::rand::seed());
+        }
+
+        THREAD_RNG.with(|rng| rng.fastrand_n(n))
+    }
+}

tokio-stream/src/wrappers.rs

@@ -0,0 +1,71 @@
+//! Wrappers for Tokio types that implement `Stream`.
+//!
+#![cfg_attr(
+    unix,
+    doc = "You are viewing documentation built under unix. To view windows-specific wrappers, change to the `x86_64-pc-windows-msvc` platform."
+)]
+#![cfg_attr(
+    windows,
+    doc = "You are viewing documentation built under windows. To view unix-specific wrappers, change to the `x86_64-unknown-linux-gnu` platform."
+)]
+
+/// Error types for the wrappers.
+pub mod errors {
+    cfg_sync! {
+        pub use crate::wrappers::broadcast::BroadcastStreamRecvError;
+    }
+}
+
+mod mpsc_bounded;
+pub use mpsc_bounded::ReceiverStream;
+
+mod mpsc_unbounded;
+pub use mpsc_unbounded::UnboundedReceiverStream;
+
+cfg_sync! {
+    mod broadcast;
+    pub use broadcast::BroadcastStream;
+
+    mod watch;
+    pub use watch::WatchStream;
+}
+
+cfg_signal! {
+    #[cfg(unix)]
+    mod signal_unix;
+    #[cfg(unix)]
+    pub use signal_unix::SignalStream;
+
+    #[cfg(windows)]
+    mod signal_windows;
+    #[cfg(windows)]
+    pub use signal_windows::{CtrlCStream, CtrlBreakStream};
+}
+
+cfg_time! {
+    mod interval;
+    pub use interval::IntervalStream;
+}
+
+cfg_net! {
+    mod tcp_listener;
+    pub use tcp_listener::TcpListenerStream;
+
+    #[cfg(unix)]
+    mod unix_listener;
+    #[cfg(unix)]
+    pub use unix_listener::UnixListenerStream;
+}
+
+cfg_io_util! {
+    mod split;
+    pub use split::SplitStream;
+
+    mod lines;
+    pub use lines::LinesStream;
+}
+
+cfg_fs! {
+    mod read_dir;
+    pub use read_dir::ReadDirStream;
+}

tokio-stream/src/wrappers/broadcast.rs

@@ -0,0 +1,63 @@
+use std::pin::Pin;
+use tokio::sync::broadcast::error::RecvError;
+use tokio::sync::broadcast::Receiver;
+
+use futures_core::Stream;
+use tokio_util::sync::ReusableBoxFuture;
+
+use std::fmt;
+use std::task::{Context, Poll};
+
+/// A wrapper around [`tokio::sync::broadcast::Receiver`] that implements [`Stream`].
+///
+/// [`tokio::sync::broadcast::Receiver`]: struct@tokio::sync::broadcast::Receiver
+/// [`Stream`]: trait@crate::Stream
+#[cfg_attr(docsrs, doc(cfg(feature = "sync")))]
+pub struct BroadcastStream<T> {
+    inner: ReusableBoxFuture<(Result<T, RecvError>, Receiver<T>)>,
+}
+
+/// An error returned from the inner stream of a [`BroadcastStream`].
+#[derive(Debug, PartialEq)]
+pub enum BroadcastStreamRecvError {
+    /// The receiver lagged too far behind. Attempting to receive again will
+    /// return the oldest message still retained by the channel.
+    ///
+    /// Includes the number of skipped messages.
+    Lagged(u64),
+}
+
+async fn make_future<T: Clone>(mut rx: Receiver<T>) -> (Result<T, RecvError>, Receiver<T>) {
+    let result = rx.recv().await;
+    (result, rx)
+}
+
+impl<T: 'static + Clone + Send> BroadcastStream<T> {
+    /// Create a new `BroadcastStream`.
+    pub fn new(rx: Receiver<T>) -> Self {
+        Self {
+            inner: ReusableBoxFuture::new(make_future(rx)),
+        }
+    }
+}
+
+impl<T: 'static + Clone + Send> Stream for BroadcastStream<T> {
+    type Item = Result<T, BroadcastStreamRecvError>;
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let (result, rx) = ready!(self.inner.poll(cx));
+        self.inner.set(make_future(rx));
+        match result {
+            Ok(item) => Poll::Ready(Some(Ok(item))),
+            Err(RecvError::Closed) => Poll::Ready(None),
+            Err(RecvError::Lagged(n)) => {
+                Poll::Ready(Some(Err(BroadcastStreamRecvError::Lagged(n))))
+            }
+        }
+    }
+}
+
+impl<T> fmt::Debug for BroadcastStream<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("BroadcastStream").finish()
+    }
+}

tokio-stream/src/wrappers/interval.rs

@@ -0,0 +1,50 @@
+use crate::Stream;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::time::{Instant, Interval};
+
+/// A wrapper around [`Interval`] that implements [`Stream`].
+///
+/// [`Interval`]: struct@tokio::time::Interval
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+#[cfg_attr(docsrs, doc(cfg(feature = "time")))]
+pub struct IntervalStream {
+    inner: Interval,
+}
+
+impl IntervalStream {
+    /// Create a new `IntervalStream`.
+    pub fn new(interval: Interval) -> Self {
+        Self { inner: interval }
+    }
+
+    /// Get back the inner `Interval`.
+    pub fn into_inner(self) -> Interval {
+        self.inner
+    }
+}
+
+impl Stream for IntervalStream {
+    type Item = Instant;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Instant>> {
+        self.inner.poll_tick(cx).map(Some)
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (std::usize::MAX, None)
+    }
+}
+
+impl AsRef<Interval> for IntervalStream {
+    fn as_ref(&self) -> &Interval {
+        &self.inner
+    }
+}
+
+impl AsMut<Interval> for IntervalStream {
+    fn as_mut(&mut self) -> &mut Interval {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/lines.rs

@@ -0,0 +1,60 @@
+use crate::Stream;
+use pin_project_lite::pin_project;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::io::{AsyncBufRead, Lines};
+
+pin_project! {
+    /// A wrapper around [`tokio::io::Lines`] that implements [`Stream`].
+    ///
+    /// [`tokio::io::Lines`]: struct@tokio::io::Lines
+    /// [`Stream`]: trait@crate::Stream
+    #[derive(Debug)]
+    #[cfg_attr(docsrs, doc(cfg(feature = "io-util")))]
+    pub struct LinesStream<R> {
+        #[pin]
+        inner: Lines<R>,
+    }
+}
+
+impl<R> LinesStream<R> {
+    /// Create a new `LinesStream`.
+    pub fn new(lines: Lines<R>) -> Self {
+        Self { inner: lines }
+    }
+
+    /// Get back the inner `Lines`.
+    pub fn into_inner(self) -> Lines<R> {
+        self.inner
+    }
+
+    /// Obtain a pinned reference to the inner `Lines<R>`.
+    #[allow(clippy::wrong_self_convention)] // https://github.com/rust-lang/rust-clippy/issues/4546
+    pub fn as_pin_mut(self: Pin<&mut Self>) -> Pin<&mut Lines<R>> {
+        self.project().inner
+    }
+}
+
+impl<R: AsyncBufRead> Stream for LinesStream<R> {
+    type Item = io::Result<String>;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        self.project()
+            .inner
+            .poll_next_line(cx)
+            .map(Result::transpose)
+    }
+}
+
+impl<R> AsRef<Lines<R>> for LinesStream<R> {
+    fn as_ref(&self) -> &Lines<R> {
+        &self.inner
+    }
+}
+
+impl<R> AsMut<Lines<R>> for LinesStream<R> {
+    fn as_mut(&mut self) -> &mut Lines<R> {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/mpsc_bounded.rs

@@ -0,0 +1,59 @@
+use crate::Stream;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::sync::mpsc::Receiver;
+
+/// A wrapper around [`tokio::sync::mpsc::Receiver`] that implements [`Stream`].
+///
+/// [`tokio::sync::mpsc::Receiver`]: struct@tokio::sync::mpsc::Receiver
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+pub struct ReceiverStream<T> {
+    inner: Receiver<T>,
+}
+
+impl<T> ReceiverStream<T> {
+    /// Create a new `ReceiverStream`.
+    pub fn new(recv: Receiver<T>) -> Self {
+        Self { inner: recv }
+    }
+
+    /// Get back the inner `Receiver`.
+    pub fn into_inner(self) -> Receiver<T> {
+        self.inner
+    }
+
+    /// Closes the receiving half of a channel without dropping it.
+    ///
+    /// This prevents any further messages from being sent on the channel while
+    /// still enabling the receiver to drain messages that are buffered. Any
+    /// outstanding [`Permit`] values will still be able to send messages.
+    ///
+    /// To guarantee no messages are dropped, after calling `close()`, you must
+    /// receive all items from the stream until `None` is returned.
+    ///
+    /// [`Permit`]: struct@tokio::sync::mpsc::Permit
+    pub fn close(&mut self) {
+        self.inner.close()
+    }
+}
+
+impl<T> Stream for ReceiverStream<T> {
+    type Item = T;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        self.inner.poll_recv(cx)
+    }
+}
+
+impl<T> AsRef<Receiver<T>> for ReceiverStream<T> {
+    fn as_ref(&self) -> &Receiver<T> {
+        &self.inner
+    }
+}
+
+impl<T> AsMut<Receiver<T>> for ReceiverStream<T> {
+    fn as_mut(&mut self) -> &mut Receiver<T> {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/mpsc_unbounded.rs

@@ -0,0 +1,53 @@
+use crate::Stream;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::sync::mpsc::UnboundedReceiver;
+
+/// A wrapper around [`tokio::sync::mpsc::UnboundedReceiver`] that implements [`Stream`].
+///
+/// [`tokio::sync::mpsc::UnboundedReceiver`]: struct@tokio::sync::mpsc::UnboundedReceiver
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+pub struct UnboundedReceiverStream<T> {
+    inner: UnboundedReceiver<T>,
+}
+
+impl<T> UnboundedReceiverStream<T> {
+    /// Create a new `UnboundedReceiverStream`.
+    pub fn new(recv: UnboundedReceiver<T>) -> Self {
+        Self { inner: recv }
+    }
+
+    /// Get back the inner `UnboundedReceiver`.
+    pub fn into_inner(self) -> UnboundedReceiver<T> {
+        self.inner
+    }
+
+    /// Closes the receiving half of a channel without dropping it.
+    ///
+    /// This prevents any further messages from being sent on the channel while
+    /// still enabling the receiver to drain messages that are buffered.
+    pub fn close(&mut self) {
+        self.inner.close()
+    }
+}
+
+impl<T> Stream for UnboundedReceiverStream<T> {
+    type Item = T;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        self.inner.poll_recv(cx)
+    }
+}
+
+impl<T> AsRef<UnboundedReceiver<T>> for UnboundedReceiverStream<T> {
+    fn as_ref(&self) -> &UnboundedReceiver<T> {
+        &self.inner
+    }
+}
+
+impl<T> AsMut<UnboundedReceiver<T>> for UnboundedReceiverStream<T> {
+    fn as_mut(&mut self) -> &mut UnboundedReceiver<T> {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/read_dir.rs

@@ -0,0 +1,47 @@
+use crate::Stream;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::fs::{DirEntry, ReadDir};
+
+/// A wrapper around [`tokio::fs::ReadDir`] that implements [`Stream`].
+///
+/// [`tokio::fs::ReadDir`]: struct@tokio::fs::ReadDir
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+#[cfg_attr(docsrs, doc(cfg(feature = "fs")))]
+pub struct ReadDirStream {
+    inner: ReadDir,
+}
+
+impl ReadDirStream {
+    /// Create a new `ReadDirStream`.
+    pub fn new(read_dir: ReadDir) -> Self {
+        Self { inner: read_dir }
+    }
+
+    /// Get back the inner `ReadDir`.
+    pub fn into_inner(self) -> ReadDir {
+        self.inner
+    }
+}
+
+impl Stream for ReadDirStream {
+    type Item = io::Result<DirEntry>;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        self.inner.poll_next_entry(cx).map(Result::transpose)
+    }
+}
+
+impl AsRef<ReadDir> for ReadDirStream {
+    fn as_ref(&self) -> &ReadDir {
+        &self.inner
+    }
+}
+
+impl AsMut<ReadDir> for ReadDirStream {
+    fn as_mut(&mut self) -> &mut ReadDir {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/signal_unix.rs

@@ -0,0 +1,46 @@
+use crate::Stream;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::signal::unix::Signal;
+
+/// A wrapper around [`Signal`] that implements [`Stream`].
+///
+/// [`Signal`]: struct@tokio::signal::unix::Signal
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+#[cfg_attr(docsrs, doc(cfg(all(unix, feature = "signal"))))]
+pub struct SignalStream {
+    inner: Signal,
+}
+
+impl SignalStream {
+    /// Create a new `SignalStream`.
+    pub fn new(interval: Signal) -> Self {
+        Self { inner: interval }
+    }
+
+    /// Get back the inner `Signal`.
+    pub fn into_inner(self) -> Signal {
+        self.inner
+    }
+}
+
+impl Stream for SignalStream {
+    type Item = ();
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<()>> {
+        self.inner.poll_recv(cx)
+    }
+}
+
+impl AsRef<Signal> for SignalStream {
+    fn as_ref(&self) -> &Signal {
+        &self.inner
+    }
+}
+
+impl AsMut<Signal> for SignalStream {
+    fn as_mut(&mut self) -> &mut Signal {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/signal_windows.rs

@@ -0,0 +1,88 @@
+use crate::Stream;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::signal::windows::{CtrlBreak, CtrlC};
+
+/// A wrapper around [`CtrlC`] that implements [`Stream`].
+///
+/// [`CtrlC`]: struct@tokio::signal::windows::CtrlC
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+#[cfg_attr(docsrs, doc(cfg(all(windows, feature = "signal"))))]
+pub struct CtrlCStream {
+    inner: CtrlC,
+}
+
+impl CtrlCStream {
+    /// Create a new `CtrlCStream`.
+    pub fn new(interval: CtrlC) -> Self {
+        Self { inner: interval }
+    }
+
+    /// Get back the inner `CtrlC`.
+    pub fn into_inner(self) -> CtrlC {
+        self.inner
+    }
+}
+
+impl Stream for CtrlCStream {
+    type Item = ();
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<()>> {
+        self.inner.poll_recv(cx)
+    }
+}
+
+impl AsRef<CtrlC> for CtrlCStream {
+    fn as_ref(&self) -> &CtrlC {
+        &self.inner
+    }
+}
+
+impl AsMut<CtrlC> for CtrlCStream {
+    fn as_mut(&mut self) -> &mut CtrlC {
+        &mut self.inner
+    }
+}
+
+/// A wrapper around [`CtrlBreak`] that implements [`Stream`].
+///
+/// [`CtrlBreak`]: struct@tokio::signal::windows::CtrlBreak
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+#[cfg_attr(docsrs, doc(cfg(all(windows, feature = "signal"))))]
+pub struct CtrlBreakStream {
+    inner: CtrlBreak,
+}
+
+impl CtrlBreakStream {
+    /// Create a new `CtrlBreakStream`.
+    pub fn new(interval: CtrlBreak) -> Self {
+        Self { inner: interval }
+    }
+
+    /// Get back the inner `CtrlBreak`.
+    pub fn into_inner(self) -> CtrlBreak {
+        self.inner
+    }
+}
+
+impl Stream for CtrlBreakStream {
+    type Item = ();
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<()>> {
+        self.inner.poll_recv(cx)
+    }
+}
+
+impl AsRef<CtrlBreak> for CtrlBreakStream {
+    fn as_ref(&self) -> &CtrlBreak {
+        &self.inner
+    }
+}
+
+impl AsMut<CtrlBreak> for CtrlBreakStream {
+    fn as_mut(&mut self) -> &mut CtrlBreak {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/split.rs

@@ -0,0 +1,60 @@
+use crate::Stream;
+use pin_project_lite::pin_project;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::io::{AsyncBufRead, Split};
+
+pin_project! {
+    /// A wrapper around [`tokio::io::Split`] that implements [`Stream`].
+    ///
+    /// [`tokio::io::Split`]: struct@tokio::io::Split
+    /// [`Stream`]: trait@crate::Stream
+    #[derive(Debug)]
+    #[cfg_attr(docsrs, doc(cfg(feature = "io-util")))]
+    pub struct SplitStream<R> {
+        #[pin]
+        inner: Split<R>,
+    }
+}
+
+impl<R> SplitStream<R> {
+    /// Create a new `SplitStream`.
+    pub fn new(split: Split<R>) -> Self {
+        Self { inner: split }
+    }
+
+    /// Get back the inner `Split`.
+    pub fn into_inner(self) -> Split<R> {
+        self.inner
+    }
+
+    /// Obtain a pinned reference to the inner `Split<R>`.
+    #[allow(clippy::wrong_self_convention)] // https://github.com/rust-lang/rust-clippy/issues/4546
+    pub fn as_pin_mut(self: Pin<&mut Self>) -> Pin<&mut Split<R>> {
+        self.project().inner
+    }
+}
+
+impl<R: AsyncBufRead> Stream for SplitStream<R> {
+    type Item = io::Result<Vec<u8>>;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        self.project()
+            .inner
+            .poll_next_segment(cx)
+            .map(Result::transpose)
+    }
+}
+
+impl<R> AsRef<Split<R>> for SplitStream<R> {
+    fn as_ref(&self) -> &Split<R> {
+        &self.inner
+    }
+}
+
+impl<R> AsMut<Split<R>> for SplitStream<R> {
+    fn as_mut(&mut self) -> &mut Split<R> {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/tcp_listener.rs

@@ -0,0 +1,54 @@
+use crate::Stream;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::net::{TcpListener, TcpStream};
+
+/// A wrapper around [`TcpListener`] that implements [`Stream`].
+///
+/// [`TcpListener`]: struct@tokio::net::TcpListener
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+#[cfg_attr(docsrs, doc(cfg(feature = "net")))]
+pub struct TcpListenerStream {
+    inner: TcpListener,
+}
+
+impl TcpListenerStream {
+    /// Create a new `TcpListenerStream`.
+    pub fn new(listener: TcpListener) -> Self {
+        Self { inner: listener }
+    }
+
+    /// Get back the inner `TcpListener`.
+    pub fn into_inner(self) -> TcpListener {
+        self.inner
+    }
+}
+
+impl Stream for TcpListenerStream {
+    type Item = io::Result<TcpStream>;
+
+    fn poll_next(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<Option<io::Result<TcpStream>>> {
+        match self.inner.poll_accept(cx) {
+            Poll::Ready(Ok((stream, _))) => Poll::Ready(Some(Ok(stream))),
+            Poll::Ready(Err(err)) => Poll::Ready(Some(Err(err))),
+            Poll::Pending => Poll::Pending,
+        }
+    }
+}
+
+impl AsRef<TcpListener> for TcpListenerStream {
+    fn as_ref(&self) -> &TcpListener {
+        &self.inner
+    }
+}
+
+impl AsMut<TcpListener> for TcpListenerStream {
+    fn as_mut(&mut self) -> &mut TcpListener {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/unix_listener.rs

@@ -0,0 +1,54 @@
+use crate::Stream;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use tokio::net::{UnixListener, UnixStream};
+
+/// A wrapper around [`UnixListener`] that implements [`Stream`].
+///
+/// [`UnixListener`]: struct@tokio::net::UnixListener
+/// [`Stream`]: trait@crate::Stream
+#[derive(Debug)]
+#[cfg_attr(docsrs, doc(cfg(all(unix, feature = "net"))))]
+pub struct UnixListenerStream {
+    inner: UnixListener,
+}
+
+impl UnixListenerStream {
+    /// Create a new `UnixListenerStream`.
+    pub fn new(listener: UnixListener) -> Self {
+        Self { inner: listener }
+    }
+
+    /// Get back the inner `UnixListener`.
+    pub fn into_inner(self) -> UnixListener {
+        self.inner
+    }
+}
+
+impl Stream for UnixListenerStream {
+    type Item = io::Result<UnixStream>;
+
+    fn poll_next(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<Option<io::Result<UnixStream>>> {
+        match self.inner.poll_accept(cx) {
+            Poll::Ready(Ok((stream, _))) => Poll::Ready(Some(Ok(stream))),
+            Poll::Ready(Err(err)) => Poll::Ready(Some(Err(err))),
+            Poll::Pending => Poll::Pending,
+        }
+    }
+}
+
+impl AsRef<UnixListener> for UnixListenerStream {
+    fn as_ref(&self) -> &UnixListener {
+        &self.inner
+    }
+}
+
+impl AsMut<UnixListener> for UnixListenerStream {
+    fn as_mut(&mut self) -> &mut UnixListener {
+        &mut self.inner
+    }
+}

tokio-stream/src/wrappers/watch.rs

@@ -0,0 +1,96 @@
+use std::pin::Pin;
+use tokio::sync::watch::Receiver;
+
+use futures_core::Stream;
+use tokio_util::sync::ReusableBoxFuture;
+
+use std::fmt;
+use std::task::{Context, Poll};
+use tokio::sync::watch::error::RecvError;
+
+/// A wrapper around [`tokio::sync::watch::Receiver`] that implements [`Stream`].
+///
+/// This stream will always start by yielding the current value when the WatchStream is polled,
+/// regardles of whether it was the initial value or sent afterwards.
+///
+/// # Examples
+///
+/// ```
+/// # #[tokio::main]
+/// # async fn main() {
+/// use tokio_stream::{StreamExt, wrappers::WatchStream};
+/// use tokio::sync::watch;
+///
+/// let (tx, rx) = watch::channel("hello");
+/// let mut rx = WatchStream::new(rx);
+///
+/// assert_eq!(rx.next().await, Some("hello"));
+///
+/// tx.send("goodbye").unwrap();
+/// assert_eq!(rx.next().await, Some("goodbye"));
+/// # }
+/// ```
+///
+/// ```
+/// # #[tokio::main]
+/// # async fn main() {
+/// use tokio_stream::{StreamExt, wrappers::WatchStream};
+/// use tokio::sync::watch;
+///
+/// let (tx, rx) = watch::channel("hello");
+/// let mut rx = WatchStream::new(rx);
+///
+/// tx.send("goodbye").unwrap();
+/// assert_eq!(rx.next().await, Some("goodbye"));
+/// # }
+/// ```
+///
+/// [`tokio::sync::watch::Receiver`]: struct@tokio::sync::watch::Receiver
+/// [`Stream`]: trait@crate::Stream
+#[cfg_attr(docsrs, doc(cfg(feature = "sync")))]
+pub struct WatchStream<T> {
+    inner: ReusableBoxFuture<(Result<(), RecvError>, Receiver<T>)>,
+}
+
+async fn make_future<T: Clone + Send + Sync>(
+    mut rx: Receiver<T>,
+) -> (Result<(), RecvError>, Receiver<T>) {
+    let result = rx.changed().await;
+    (result, rx)
+}
+
+impl<T: 'static + Clone + Unpin + Send + Sync> WatchStream<T> {
+    /// Create a new `WatchStream`.
+    pub fn new(rx: Receiver<T>) -> Self {
+        Self {
+            inner: ReusableBoxFuture::new(async move { (Ok(()), rx) }),
+        }
+    }
+}
+
+impl<T: Clone + 'static + Send + Sync> Stream for WatchStream<T> {
+    type Item = T;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let (result, rx) = ready!(self.inner.poll(cx));
+        match result {
+            Ok(_) => {
+                let received = (*rx.borrow()).clone();
+                self.inner.set(make_future(rx));
+                Poll::Ready(Some(received))
+            }
+            Err(_) => {
+                self.inner.set(make_future(rx));
+                Poll::Ready(None)
+            }
+        }
+    }
+}
+
+impl<T> Unpin for WatchStream<T> {}
+
+impl<T> fmt::Debug for WatchStream<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("WatchStream").finish()
+    }
+}

tokio-stream/tests/async_send_sync.rs

@@ -0,0 +1,105 @@
+use std::rc::Rc;
+
+#[allow(dead_code)]
+type BoxStream<T> = std::pin::Pin<Box<dyn tokio_stream::Stream<Item = T>>>;
+
+#[allow(dead_code)]
+fn require_send<T: Send>(_t: &T) {}
+#[allow(dead_code)]
+fn require_sync<T: Sync>(_t: &T) {}
+#[allow(dead_code)]
+fn require_unpin<T: Unpin>(_t: &T) {}
+
+#[allow(dead_code)]
+struct Invalid;
+
+trait AmbiguousIfSend<A> {
+    fn some_item(&self) {}
+}
+impl<T: ?Sized> AmbiguousIfSend<()> for T {}
+impl<T: ?Sized + Send> AmbiguousIfSend<Invalid> for T {}
+
+trait AmbiguousIfSync<A> {
+    fn some_item(&self) {}
+}
+impl<T: ?Sized> AmbiguousIfSync<()> for T {}
+impl<T: ?Sized + Sync> AmbiguousIfSync<Invalid> for T {}
+
+trait AmbiguousIfUnpin<A> {
+    fn some_item(&self) {}
+}
+impl<T: ?Sized> AmbiguousIfUnpin<()> for T {}
+impl<T: ?Sized + Unpin> AmbiguousIfUnpin<Invalid> for T {}
+
+macro_rules! into_todo {
+    ($typ:ty) => {{
+        let x: $typ = todo!();
+        x
+    }};
+}
+
+macro_rules! async_assert_fn {
+    ($($f:ident $(< $($generic:ty),* > )? )::+($($arg:ty),*): Send & Sync) => {
+        #[allow(unreachable_code)]
+        #[allow(unused_variables)]
+        const _: fn() = || {
+            let f = $($f $(::<$($generic),*>)? )::+( $( into_todo!($arg) ),* );
+            require_send(&f);
+            require_sync(&f);
+        };
+    };
+    ($($f:ident $(< $($generic:ty),* > )? )::+($($arg:ty),*): Send & !Sync) => {
+        #[allow(unreachable_code)]
+        #[allow(unused_variables)]
+        const _: fn() = || {
+            let f = $($f $(::<$($generic),*>)? )::+( $( into_todo!($arg) ),* );
+            require_send(&f);
+            AmbiguousIfSync::some_item(&f);
+        };
+    };
+    ($($f:ident $(< $($generic:ty),* > )? )::+($($arg:ty),*): !Send & Sync) => {
+        #[allow(unreachable_code)]
+        #[allow(unused_variables)]
+        const _: fn() = || {
+            let f = $($f $(::<$($generic),*>)? )::+( $( into_todo!($arg) ),* );
+            AmbiguousIfSend::some_item(&f);
+            require_sync(&f);
+        };
+    };
+    ($($f:ident $(< $($generic:ty),* > )? )::+($($arg:ty),*): !Send & !Sync) => {
+        #[allow(unreachable_code)]
+        #[allow(unused_variables)]
+        const _: fn() = || {
+            let f = $($f $(::<$($generic),*>)? )::+( $( into_todo!($arg) ),* );
+            AmbiguousIfSend::some_item(&f);
+            AmbiguousIfSync::some_item(&f);
+        };
+    };
+    ($($f:ident $(< $($generic:ty),* > )? )::+($($arg:ty),*): !Unpin) => {
+        #[allow(unreachable_code)]
+        #[allow(unused_variables)]
+        const _: fn() = || {
+            let f = $($f $(::<$($generic),*>)? )::+( $( into_todo!($arg) ),* );
+            AmbiguousIfUnpin::some_item(&f);
+        };
+    };
+    ($($f:ident $(< $($generic:ty),* > )? )::+($($arg:ty),*): Unpin) => {
+        #[allow(unreachable_code)]
+        #[allow(unused_variables)]
+        const _: fn() = || {
+            let f = $($f $(::<$($generic),*>)? )::+( $( into_todo!($arg) ),* );
+            require_unpin(&f);
+        };
+    };
+}
+
+async_assert_fn!(tokio_stream::empty<Rc<u8>>(): Send & Sync);
+async_assert_fn!(tokio_stream::pending<Rc<u8>>(): Send & Sync);
+async_assert_fn!(tokio_stream::iter(std::vec::IntoIter<u8>): Send & Sync);
+
+async_assert_fn!(tokio_stream::StreamExt::next(&mut BoxStream<()>): !Unpin);
+async_assert_fn!(tokio_stream::StreamExt::try_next(&mut BoxStream<Result<(), ()>>): !Unpin);
+async_assert_fn!(tokio_stream::StreamExt::all(&mut BoxStream<()>, fn(())->bool): !Unpin);
+async_assert_fn!(tokio_stream::StreamExt::any(&mut BoxStream<()>, fn(())->bool): !Unpin);
+async_assert_fn!(tokio_stream::StreamExt::fold(&mut BoxStream<()>, (), fn((), ())->()): !Unpin);
+async_assert_fn!(tokio_stream::StreamExt::collect<Vec<()>>(&mut BoxStream<()>): !Unpin);

tokio-stream/tests/stream_chain.rs

@@ -1,7 +1,12 @@
-use tokio::stream::{self, Stream, StreamExt};
-use tokio::sync::mpsc;
+use tokio_stream::{self as stream, Stream, StreamExt};
 use tokio_test::{assert_pending, assert_ready, task};
 
+mod support {
+    pub(crate) mod mpsc;
+}
+
+use support::mpsc;
+
 #[tokio::test]
 async fn basic_usage() {
     let one = stream::iter(vec![1, 2, 3]);
@@ -36,8 +41,8 @@ async fn basic_usage() {
 
 #[tokio::test]
 async fn pending_first() {
-    let (tx1, rx1) = mpsc::unbounded_channel();
-    let (tx2, rx2) = mpsc::unbounded_channel();
+    let (tx1, rx1) = mpsc::unbounded_channel_stream();
+    let (tx2, rx2) = mpsc::unbounded_channel_stream();
 
     let mut stream = task::spawn(rx1.chain(rx2));
     assert_eq!(stream.size_hint(), (0, None));
@@ -74,7 +79,7 @@ async fn pending_first() {
 fn size_overflow() {
     struct Monster;
 
-    impl tokio::stream::Stream for Monster {
+    impl tokio_stream::Stream for Monster {
         type Item = ();
         fn poll_next(
             self: std::pin::Pin<&mut Self>,

tokio-stream/tests/stream_collect.rs

@@ -1,7 +1,12 @@
-use tokio::stream::{self, StreamExt};
-use tokio::sync::mpsc;
+use tokio_stream::{self as stream, StreamExt};
 use tokio_test::{assert_pending, assert_ready, assert_ready_err, assert_ready_ok, task};
 
+mod support {
+    pub(crate) mod mpsc;
+}
+
+use support::mpsc;
+
 #[allow(clippy::let_unit_value)]
 #[tokio::test]
 async fn empty_unit() {
@@ -37,7 +42,7 @@ async fn empty_result() {
 
 #[tokio::test]
 async fn collect_vec_items() {
-    let (tx, rx) = mpsc::unbounded_channel();
+    let (tx, rx) = mpsc::unbounded_channel_stream();
     let mut fut = task::spawn(rx.collect::<Vec<i32>>());
 
     assert_pending!(fut.poll());
@@ -58,7 +63,8 @@ async fn collect_vec_items() {
 
 #[tokio::test]
 async fn collect_string_items() {
-    let (tx, rx) = mpsc::unbounded_channel();
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+
     let mut fut = task::spawn(rx.collect::<String>());
 
     assert_pending!(fut.poll());
@@ -79,7 +85,8 @@ async fn collect_string_items() {
 
 #[tokio::test]
 async fn collect_str_items() {
-    let (tx, rx) = mpsc::unbounded_channel();
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+
     let mut fut = task::spawn(rx.collect::<String>());
 
     assert_pending!(fut.poll());
@@ -100,7 +107,8 @@ async fn collect_str_items() {
 
 #[tokio::test]
 async fn collect_results_ok() {
-    let (tx, rx) = mpsc::unbounded_channel();
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+
     let mut fut = task::spawn(rx.collect::<Result<String, &str>>());
 
     assert_pending!(fut.poll());
@@ -121,7 +129,8 @@ async fn collect_results_ok() {
 
 #[tokio::test]
 async fn collect_results_err() {
-    let (tx, rx) = mpsc::unbounded_channel();
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+
     let mut fut = task::spawn(rx.collect::<Result<String, &str>>());
 
     assert_pending!(fut.poll());

tokio-stream/tests/stream_empty.rs

@@ -1,4 +1,4 @@
-use tokio::stream::{self, Stream, StreamExt};
+use tokio_stream::{self as stream, Stream, StreamExt};
 
 #[tokio::test]
 async fn basic_usage() {

tokio-stream/tests/stream_fuse.rs

@@ -1,4 +1,4 @@
-use tokio::stream::{Stream, StreamExt};
+use tokio_stream::{Stream, StreamExt};
 
 use std::pin::Pin;
 use std::task::{Context, Poll};

tokio-stream/tests/stream_iter.rs

@@ -1,4 +1,4 @@
-use tokio::stream;
+use tokio_stream as stream;
 use tokio_test::task;
 
 use std::iter;

tokio-stream/tests/stream_merge.rs

@@ -1,8 +1,13 @@
-use tokio::stream::{self, Stream, StreamExt};
-use tokio::sync::mpsc;
+use tokio_stream::{self as stream, Stream, StreamExt};
 use tokio_test::task;
 use tokio_test::{assert_pending, assert_ready};
 
+mod support {
+    pub(crate) mod mpsc;
+}
+
+use support::mpsc;
+
 #[tokio::test]
 async fn merge_sync_streams() {
     let mut s = stream::iter(vec![0, 2, 4, 6]).merge(stream::iter(vec![1, 3, 5]));
@@ -18,8 +23,8 @@ async fn merge_sync_streams() {
 
 #[tokio::test]
 async fn merge_async_streams() {
-    let (tx1, rx1) = mpsc::unbounded_channel();
-    let (tx2, rx2) = mpsc::unbounded_channel();
+    let (tx1, rx1) = mpsc::unbounded_channel_stream();
+    let (tx2, rx2) = mpsc::unbounded_channel_stream();
 
     let mut rx = task::spawn(rx1.merge(rx2));
 
@@ -57,7 +62,7 @@ async fn merge_async_streams() {
 fn size_overflow() {
     struct Monster;
 
-    impl tokio::stream::Stream for Monster {
+    impl tokio_stream::Stream for Monster {
         type Item = ();
         fn poll_next(
             self: std::pin::Pin<&mut Self>,

tokio-stream/tests/stream_once.rs

@@ -1,4 +1,4 @@
-use tokio::stream::{self, Stream, StreamExt};
+use tokio_stream::{self as stream, Stream, StreamExt};
 
 #[tokio::test]
 async fn basic_usage() {

tokio-stream/tests/stream_pending.rs

@@ -1,4 +1,4 @@
-use tokio::stream::{self, Stream, StreamExt};
+use tokio_stream::{self as stream, Stream, StreamExt};
 use tokio_test::{assert_pending, task};
 
 #[tokio::test]

tokio-stream/tests/stream_stream_map.rs

@@ -1,7 +1,12 @@
-use tokio::stream::{self, pending, Stream, StreamExt, StreamMap};
-use tokio::sync::mpsc;
+use tokio_stream::{self as stream, pending, Stream, StreamExt, StreamMap};
 use tokio_test::{assert_ok, assert_pending, assert_ready, task};
 
+mod support {
+    pub(crate) mod mpsc;
+}
+
+use support::mpsc;
+
 use std::pin::Pin;
 
 macro_rules! assert_ready_some {
@@ -38,7 +43,8 @@ async fn empty() {
 #[tokio::test]
 async fn single_entry() {
     let mut map = task::spawn(StreamMap::new());
-    let (tx, rx) = mpsc::unbounded_channel();
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+    let rx = Box::pin(rx);
 
     assert_ready_none!(map.poll_next());
 
@@ -76,8 +82,11 @@ async fn single_entry() {
 #[tokio::test]
 async fn multiple_entries() {
     let mut map = task::spawn(StreamMap::new());
-    let (tx1, rx1) = mpsc::unbounded_channel();
-    let (tx2, rx2) = mpsc::unbounded_channel();
+    let (tx1, rx1) = mpsc::unbounded_channel_stream();
+    let (tx2, rx2) = mpsc::unbounded_channel_stream();
+
+    let rx1 = Box::pin(rx1);
+    let rx2 = Box::pin(rx2);
 
     map.insert("foo", rx1);
     map.insert("bar", rx2);
@@ -132,7 +141,9 @@ async fn multiple_entries() {
 #[tokio::test]
 async fn insert_remove() {
     let mut map = task::spawn(StreamMap::new());
-    let (tx, rx) = mpsc::unbounded_channel();
+    let (tx, rx) = mpsc::unbounded_channel_stream();
+
+    let rx = Box::pin(rx);
 
     assert_ready_none!(map.poll_next());
 
@@ -160,8 +171,11 @@ async fn insert_remove() {
 #[tokio::test]
 async fn replace() {
     let mut map = task::spawn(StreamMap::new());
-    let (tx1, rx1) = mpsc::unbounded_channel();
-    let (tx2, rx2) = mpsc::unbounded_channel();
+    let (tx1, rx1) = mpsc::unbounded_channel_stream();
+    let (tx2, rx2) = mpsc::unbounded_channel_stream();
+
+    let rx1 = Box::pin(rx1);
+    let rx2 = Box::pin(rx2);
 
     assert!(map.insert("foo", rx1).is_none());
 

tokio-stream/tests/stream_timeout.rs

@@ -1,7 +1,7 @@
 #![cfg(feature = "full")]
 
-use tokio::stream::{self, StreamExt};
 use tokio::time::{self, sleep, Duration};
+use tokio_stream::{self, StreamExt};
 use tokio_test::*;
 
 use futures::StreamExt as _;
@@ -78,7 +78,7 @@ async fn return_elapsed_errors_only_once() {
     // error is returned.
     assert_pending!(stream.poll_next());
     //
-    time::advance(ms(50)).await;
+    time::advance(ms(51)).await;
     let v = assert_ready!(stream.poll_next());
     assert!(v.unwrap().is_err()); // timeout!
 

tokio-stream/tests/support/mpsc.rs

@@ -0,0 +1,15 @@
+use async_stream::stream;
+use tokio::sync::mpsc::{self, UnboundedSender};
+use tokio_stream::Stream;
+
+pub fn unbounded_channel_stream<T: Unpin>() -> (UnboundedSender<T>, impl Stream<Item = T>) {
+    let (tx, mut rx) = mpsc::unbounded_channel();
+
+    let stream = stream! {
+        while let Some(item) = rx.recv().await {
+            yield item;
+        }
+    };
+
+    (tx, stream)
+}

tokio-stream/tests/time_throttle.rs

@@ -1,8 +1,8 @@
 #![warn(rust_2018_idioms)]
 #![cfg(feature = "full")]
 
-use tokio::stream::StreamExt;
 use tokio::time;
+use tokio_stream::StreamExt;
 use tokio_test::*;
 
 use std::time::Duration;

tokio-test/CHANGELOG.md

@@ -1,3 +1,13 @@
+# 0.4.1 (March 10, 2021)
+
+- Fix `io::Mock` to be `Send` and `Sync` ([#3594])
+
+[#3594]: https://github.com/tokio-rs/tokio/pull/3594
+
+# 0.4.0 (December 23, 2020)
+
+- Track `tokio` 1.0 release.
+
 # 0.3.0 (October 15, 2020)
 
 - Track `tokio` 0.3 release.

tokio-test/Cargo.toml

@@ -2,32 +2,32 @@
 name = "tokio-test"
 # When releasing to crates.io:
 # - Remove path dependencies
-# - Update html_root_url.
 # - Update doc url
 #   - Cargo.toml
 # - Update CHANGELOG.md.
-# - Create "v0.3.x" git tag.
-version = "0.3.0"
+# - Create "tokio-test-0.4.x" git tag.
+version = "0.4.1"
 edition = "2018"
 authors = ["Tokio Contributors <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/tokio-rs/tokio"
 homepage = "https://tokio.rs"
-documentation = "https://docs.rs/tokio-test/0.3.0/tokio_test"
+documentation = "https://docs.rs/tokio-test/0.4.1/tokio_test"
 description = """
 Testing utilities for Tokio- and futures-based code
 """
 categories = ["asynchronous", "testing"]
-publish = false
 
 [dependencies]
-tokio = { version = "0.3.0", path = "../tokio", features = ["rt", "stream", "sync", "time", "test-util"] }
+tokio = { version = "1.2.0", path = "../tokio", features = ["rt", "sync", "time", "test-util"] }
+tokio-stream = { version = "0.1", path = "../tokio-stream" }
+async-stream = "0.3"
 
-bytes = "0.5.0"
+bytes = "1.0.0"
 futures-core = "0.3.0"
 
 [dev-dependencies]
-tokio = { version = "0.3.0", path = "../tokio", features = ["full"] }
+tokio = { version = "1.2.0", path = "../tokio", features = ["full"] }
 futures-util = "0.3.0"
 
 [package.metadata.docs.rs]

tokio-test/LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2019 Tokio Contributors
+Copyright (c) 2021 Tokio Contributors
 
 Permission is hereby granted, free of charge, to any
 person obtaining a copy of this software and associated

tokio-test/src/io.rs

@@ -21,9 +21,11 @@
 use tokio::io::{AsyncRead, AsyncWrite, ReadBuf};
 use tokio::sync::mpsc;
 use tokio::time::{self, Duration, Instant, Sleep};
+use tokio_stream::wrappers::UnboundedReceiverStream;
 
-use futures_core::ready;
+use futures_core::{ready, Stream};
 use std::collections::VecDeque;
+use std::fmt;
 use std::future::Future;
 use std::pin::Pin;
 use std::sync::Arc;
@@ -63,13 +65,12 @@ enum Action {
     WriteError(Option<Arc<io::Error>>),
 }
 
-#[derive(Debug)]
 struct Inner {
     actions: VecDeque<Action>,
     waiting: Option<Instant>,
-    sleep: Option<Sleep>,
+    sleep: Option<Pin<Box<Sleep>>>,
     read_wait: Option<Waker>,
-    rx: mpsc::UnboundedReceiver<Action>,
+    rx: UnboundedReceiverStream<Action>,
 }
 
 impl Builder {
@@ -186,6 +187,8 @@ impl Inner {
     fn new(actions: VecDeque<Action>) -> (Inner, Handle) {
         let (tx, rx) = mpsc::unbounded_channel();
 
+        let rx = UnboundedReceiverStream::new(rx);
+
         let inner = Inner {
             actions,
             sleep: None,
@@ -200,8 +203,6 @@ impl Inner {
     }
 
     fn poll_action(&mut self, cx: &mut task::Context<'_>) -> Poll<Option<Action>> {
-        use futures_core::stream::Stream;
-
         Pin::new(&mut self.rx).poll_next(cx)
     }
 
@@ -365,7 +366,7 @@ impl AsyncRead for Mock {
                 Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                     if let Some(rem) = self.inner.remaining_wait() {
                         let until = Instant::now() + rem;
-                        self.inner.sleep = Some(time::sleep_until(until));
+                        self.inner.sleep = Some(Box::pin(time::sleep_until(until)));
                     } else {
                         self.inner.read_wait = Some(cx.waker().clone());
                         return Poll::Pending;
@@ -410,7 +411,7 @@ impl AsyncWrite for Mock {
                 Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                     if let Some(rem) = self.inner.remaining_wait() {
                         let until = Instant::now() + rem;
-                        self.inner.sleep = Some(time::sleep_until(until));
+                        self.inner.sleep = Some(Box::pin(time::sleep_until(until)));
                     } else {
                         panic!("unexpected WouldBlock");
                     }
@@ -485,3 +486,9 @@ fn is_task_ctx() -> bool {
     r
 }
 */
+
+impl fmt::Debug for Inner {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Inner {{...}}")
+    }
+}

tokio-test/src/lib.rs

@@ -1,4 +1,3 @@
-#![doc(html_root_url = "https://docs.rs/tokio-test/0.3.0")]
 #![warn(
     missing_debug_implementations,
     missing_docs,
@@ -22,9 +21,9 @@ pub mod task;
 /// future completes.
 ///
 /// For more information, see the documentation for
-/// [`tokio::runtime::current_thread::Runtime::block_on`][runtime-block-on].
+/// [`tokio::runtime::Runtime::block_on`][runtime-block-on].
 ///
-/// [runtime-block-on]: https://docs.rs/tokio/0.2.0-alpha.2/tokio/runtime/current_thread/struct.Runtime.html#method.block_on
+/// [runtime-block-on]: https://docs.rs/tokio/1.3.0/tokio/runtime/struct.Runtime.html#method.block_on
 pub fn block_on<F: std::future::Future>(future: F) -> F::Output {
     use tokio::runtime;
 

tokio-test/src/task.rs

@@ -9,7 +9,7 @@ use std::pin::Pin;
 use std::sync::{Arc, Condvar, Mutex};
 use std::task::{Context, Poll, RawWaker, RawWakerVTable, Waker};
 
-use tokio::stream::Stream;
+use tokio_stream::Stream;
 
 /// TODO: dox
 pub fn spawn<T>(task: T) -> Spawn<T> {