util: switch tokio-util from log to tracing (#4539)

tokio-util/Cargo.toml

@@ -25,7 +25,7 @@ full = ["codec", "compat", "io-util", "time", "net", "rt"]
 
 net = ["tokio/net"]
 compat = ["futures-io",]
-codec = []
+codec = ["tracing"]
 time = ["tokio/time","slab"]
 io = []
 io-util = ["io", "tokio/rt", "tokio/io-util"]
@@ -41,9 +41,9 @@ futures-core = "0.3.0"
 futures-sink = "0.3.0"
 futures-io = { version = "0.3.0", optional = true }
 futures-util = { version = "0.3.0", optional = true }
-log = "0.4"
 pin-project-lite = "0.2.0"
 slab = { version = "0.4.4", optional = true } # Backs `DelayQueue`
+tracing = { version = "0.1.25", optional = true }
 
 [dev-dependencies]
 tokio = { version = "1.0.0", path = "../tokio", features = ["full"] }

tokio-util/src/codec/framed_impl.rs

@@ -7,12 +7,12 @@ use tokio::io::{AsyncRead, AsyncWrite};
 use bytes::BytesMut;
 use futures_core::ready;
 use futures_sink::Sink;
-use log::trace;
 use pin_project_lite::pin_project;
 use std::borrow::{Borrow, BorrowMut};
 use std::io;
 use std::pin::Pin;
 use std::task::{Context, Poll};
+use tracing::trace;
 
 pin_project! {
     #[derive(Debug)]
@@ -278,7 +278,7 @@ where
 
         while !pinned.state.borrow_mut().buffer.is_empty() {
             let WriteFrame { buffer } = pinned.state.borrow_mut();
-            trace!("writing; remaining={}", buffer.len());
+            trace!(remaining = buffer.len(), "writing;");
 
             let n = ready!(poll_write_buf(pinned.inner.as_mut(), cx, buffer))?;