Update Rust crate tokio to 1.18

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
tokio (source)	dependencies	minor	1.17 -> 1.18

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Release Notes

tokio-rs/tokio

v1.18.0

Compare Source

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 (Ids
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)

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