* use dyn Trait syntax where appropriate
recent rust nightly started warning that not using `dyn` was
deprecated. This requires MSRV 1.27.0+.
* rustfmt fallout from dyn additions
* stop explicit allow of rust_2018_idioms
* more dyn Trait syntax
* drop tokio-macros from 0.1.x workspace
Since tokio-macros specifies an edition=2018, we would otherwise
require MSRV 1.31.0 to build/test it. And tokio-macros isn't used with
tokio 0.1.x.
* reactor: narrow tokio-io-pool dev dep to 0.1.4
Since 0.1.5-6 is now a edition=2018 crate, which has effective MSRV
1.31.0.
* narrow tempfile dev-dep to avoid MSRV bump
tempfile 3.1.0 pulls in rand 0.7.0 and is MSRV 1.32.0
* narrow flate2 dev-dep to avoid MSRV bump
flate2 1.0.10-11 have MSRV 1.34.0.
github refs: alexcrichton/flate2-rs#207
* fs: drop deprecated tempdir crate use in tests
In particular because it pulls in old rand duplicates. Replace use
with tempfile::tempdir() which has been available since tempfile
3.0.0.
backport-of: #1312
* increase CI MSRV to 1.28.0
This patch adds a new crate: tokio-fs. This crate provides a wrapper
around `std` functionality that can only be performed using blocking
operations. This primarily includes filesystem operations, but it also
includes standard input, output, and error access as these streams
cannot be safely switched to non-blocking mode in a portable way.
These wrappers call the `std` functions from within a `blocking`
annotation which allows the runtime to compensate for the fact that the
thread will potentially remain blocked in a system call.
David Kellum