tokio: prepare to release v1.18.0 (#4641)

# 1.18.0 (April 27, 2022)

This release adds a number of new APIs in `tokio::net`, `tokio::signal`, and
`tokio::sync`. In addition, it adds new unstable APIs to `tokio::task` (`Id`s
for uniquely identifying a task, and `AbortHandle` for remotely cancelling a
task), as well as a number of bugfixes.

### Fixed

- blocking: add missing `#[track_caller]` for `spawn_blocking` ([#4616])
- macros: fix `select` macro to process 64 branches ([#4519])
- net: fix `try_io` methods not calling Mio's `try_io` internally ([#4582])
- runtime: recover when OS fails to spawn a new thread ([#4485])

### Added

- macros: support setting a custom crate name for `#[tokio::main]` and
  `#[tokio::test]` ([#4613])
- net: add `UdpSocket::peer_addr` ([#4611])
- net: add `try_read_buf` method for named pipes ([#4626])
- signal: add `SignalKind` `Hash`/`Eq` impls and `c_int` conversion ([#4540])
- signal: add support for signals up to `SIGRTMAX` ([#4555])
- sync: add `watch::Sender::send_modify` method ([#4310])
- sync: add `broadcast::Receiver::len` method ([#4542])
- sync: add `watch::Receiver::same_channel` method ([#4581])
- sync: implement `Clone` for `RecvError` types ([#4560])

### Changed

- update `nix` to 0.24, limit features ([#4631])
- update `mio` to 0.8.1 ([#4582])
- macros: rename `tokio::select!`'s internal `util` module ([#4543])
- runtime: use `Vec::with_capacity` when building runtime ([#4553])

### Documented

- improve docs for `tokio_unstable` ([#4524])
- runtime: include more documentation for thread_pool/worker ([#4511])
- runtime: update `Handle::current`'s docs to mention `EnterGuard` ([#4567])
- time: clarify platform specific timer resolution ([#4474])
- signal: document that `Signal::recv` is cancel-safe ([#4634])
- sync: `UnboundedReceiver` close docs ([#4548])

### Unstable

The following changes only apply when building with `--cfg tokio_unstable`:

- task: add `task::Id` type ([#4630])
- task: add `AbortHandle` type for cancelling tasks in a `JoinSet` ([#4530],
  [#4640])
- task: fix missing `doc(cfg(...))` attributes for `JoinSet` ([#4531])
- task: fix broken link in `AbortHandle` RustDoc ([#4545])
- metrics: add initial IO driver metrics ([#4507])

[#4616]: #4616
[#4519]: #4519
[#4582]: #4582
[#4485]: #4485
[#4613]: #4613
[#4611]: #4611
[#4626]: #4626
[#4540]: #4540
[#4555]: #4555
[#4310]: #4310
[#4542]: #4542
[#4581]: #4581
[#4560]: #4560
[#4631]: #4631
[#4582]: #4582
[#4543]: #4543
[#4553]: #4553
[#4524]: #4524
[#4511]: #4511
[#4567]: #4567
[#4474]: #4474
[#4634]: #4634
[#4548]: #4548
[#4630]: #4630
[#4530]: #4530
[#4640]: #4640
[#4531]: #4531
[#4545]: #4545
[#4507]: #4507

Signed-off-by: Eliza Weisman <eliza@buoyant.io>

Author: hawkw

tokio/CHANGELOG.md

@@ -1,3 +1,87 @@
+# 1.18.0 (April 27, 2022)
+
+This release adds a number of new APIs in `tokio::net`, `tokio::signal`, and
+`tokio::sync`. In addition, it adds new unstable APIs to `tokio::task` (`Id`s
+for uniquely identifying a task, and `AbortHandle` for remotely cancelling a
+task), as well as a number of bugfixes.
+
+### Fixed
+
+- blocking: add missing `#[track_caller]` for `spawn_blocking` ([#4616])
+- macros: fix `select` macro to process 64 branches ([#4519])
+- net: fix `try_io` methods not calling Mio's `try_io` internally ([#4582])
+- runtime: recover when OS fails to spawn a new thread ([#4485])
+
+### Added
+
+- macros: support setting a custom crate name for `#[tokio::main]` and
+  `#[tokio::test]` ([#4613])
+- net: add `UdpSocket::peer_addr` ([#4611])
+- net: add `try_read_buf` method for named pipes ([#4626])
+- signal: add `SignalKind` `Hash`/`Eq` impls and `c_int` conversion ([#4540])
+- signal: add support for signals up to `SIGRTMAX` ([#4555])
+- sync: add `watch::Sender::send_modify` method ([#4310])
+- sync: add `broadcast::Receiver::len` method ([#4542])
+- sync: add `watch::Receiver::same_channel` method ([#4581])
+- sync: implement `Clone` for `RecvError` types ([#4560])
+
+### Changed
+
+- update `mio` to 0.8.1 ([#4582])
+- macros: rename `tokio::select!`'s internal `util` module ([#4543])
+- runtime: use `Vec::with_capacity` when building runtime ([#4553])
+
+### Documented
+
+- improve docs for `tokio_unstable` ([#4524])
+- runtime: include more documentation for thread_pool/worker ([#4511])
+- runtime: update `Handle::current`'s docs to mention `EnterGuard` ([#4567])
+- time: clarify platform specific timer resolution ([#4474])
+- signal: document that `Signal::recv` is cancel-safe ([#4634])
+- sync: `UnboundedReceiver` close docs ([#4548])
+
+### Unstable
+
+The following changes only apply when building with `--cfg tokio_unstable`:
+
+- task: add `task::Id` type ([#4630])
+- task: add `AbortHandle` type for cancelling tasks in a `JoinSet` ([#4530],
+  [#4640])
+- task: fix missing `doc(cfg(...))` attributes for `JoinSet` ([#4531])
+- task: fix broken link in `AbortHandle` RustDoc ([#4545])
+- metrics: add initial IO driver metrics ([#4507])
+
+
+[#4616]: https://github.com/tokio-rs/tokio/pull/4616
+[#4519]: https://github.com/tokio-rs/tokio/pull/4519
+[#4582]: https://github.com/tokio-rs/tokio/pull/4582
+[#4485]: https://github.com/tokio-rs/tokio/pull/4485
+[#4613]: https://github.com/tokio-rs/tokio/pull/4613
+[#4611]: https://github.com/tokio-rs/tokio/pull/4611
+[#4626]: https://github.com/tokio-rs/tokio/pull/4626
+[#4540]: https://github.com/tokio-rs/tokio/pull/4540
+[#4555]: https://github.com/tokio-rs/tokio/pull/4555
+[#4310]: https://github.com/tokio-rs/tokio/pull/4310
+[#4542]: https://github.com/tokio-rs/tokio/pull/4542
+[#4581]: https://github.com/tokio-rs/tokio/pull/4581
+[#4560]: https://github.com/tokio-rs/tokio/pull/4560
+[#4631]: https://github.com/tokio-rs/tokio/pull/4631
+[#4582]: https://github.com/tokio-rs/tokio/pull/4582
+[#4543]: https://github.com/tokio-rs/tokio/pull/4543
+[#4553]: https://github.com/tokio-rs/tokio/pull/4553
+[#4524]: https://github.com/tokio-rs/tokio/pull/4524
+[#4511]: https://github.com/tokio-rs/tokio/pull/4511
+[#4567]: https://github.com/tokio-rs/tokio/pull/4567
+[#4474]: https://github.com/tokio-rs/tokio/pull/4474
+[#4634]: https://github.com/tokio-rs/tokio/pull/4634
+[#4548]: https://github.com/tokio-rs/tokio/pull/4548
+[#4630]: https://github.com/tokio-rs/tokio/pull/4630
+[#4530]: https://github.com/tokio-rs/tokio/pull/4530
+[#4640]: https://github.com/tokio-rs/tokio/pull/4640
+[#4531]: https://github.com/tokio-rs/tokio/pull/4531
+[#4545]: https://github.com/tokio-rs/tokio/pull/4545
+[#4507]: https://github.com/tokio-rs/tokio/pull/4507
+
 # 1.17.0 (February 16, 2022)
 
 This release updates the minimum supported Rust version (MSRV) to 1.49, the