Bump tokio from 0.2.22 to 0.3.1

[dependabot-preview]

Bumps tokio from 0.2.22 to 0.3.1.

Release notes

Sourced from tokio's releases.

Tokio v0.3.1

This release fixes a use-after-free in the IO driver. Additionally, the read_buf and write_buf methods have been added back to the IO traits, as the bytes crate is now on track to reach version 1.0 together with Tokio.

Fixed

• net: fix use-after-free (#3019).
• fs: ensure buffered data is written on shutdown (#3009).

Added

• io: copy_buf() (#2884).
• io: AsyncReadExt::read_buf(), AsyncReadExt::write_buf() for working with Buf/BufMut (#3003).
• rt: Runtime::spawn_blocking() (#2980).
• sync: watch::Sender::is_closed() (#2991).

Tokio v0.3.0

This represents a 1.0 beta release. APIs are polished and future-proofed. APIs not included for 1.0 stabilization have been removed.

Biggest changes are:

• I/O driver internal rewrite. The windows implementation includes significant changes.
• Runtime API is polished, especially with how it interacts with feature flag combinations.
• Feature flags are simplified
  • rt-core and rt-util are combined to rt
  • rt-threaded is renamed to rt-multi-thread to match builder API
  • tcp, udp, uds, dns are combied to net.
  • parking_lot is included with full

Changes

• meta: Minimum supported Rust version is now 1.45.
• io: AsyncRead trait now takes ReadBuf in order to safely handle reading into uninitialized memory (#2758).
• io: Internal I/O driver storage is now able to compact (#2757).
• rt: Runtime::block_on now takes &self (#2782).
• sync: watch reworked to decouple receiving a change notification from receiving the value (#2814, #2806).
• sync: Notify::notify is renamed to notify_one (#2822).
• process: Child::kill is now an async fn that cleans zombies (#2823).
• sync: use const fn constructors as possible (#2833, #2790)
• signal: reduce cross-thread notification (#2835).
• net: tcp,udp,uds types support operations with &self (#2828, #2919, #2934).
• sync: blocking mpsc channel supports send with &self (#2861).
• time: rename delay_for and delay_until to sleep and sleep_until (#2826).
• io: upgrade to mio 0.7 (#2893).
• io: AsyncSeek trait is tweaked (#2885).
• fs: File operations take &self (#2930).
• rt: runtime API, and #[tokio::main] macro polish (#2876)

Commits

• d14cbf9 chore: prepare v0.3.1 release (#3021)
• 8bfb1c9 sync: revert Clone impl for broadcast::Receiver (#3020)
• b48fec9 net: fix use-after-free in slab compaction (#3019)
• 8dbc3c7 io: add AsyncReadExt::read_buf (#3003)
• 7fbfa9b tokio: deduplicate spawn_blocking (#3017)
• 7d7b79e sync: add is_closed method to watch sender (#2991)
• 8f37544 io: explain how to determine number of bytes read in AsyncRead (#3011)
• 43d0714 sync: remove extra clone in Semaphore::[try_]acquire_owned (#3015)
• 16e272e fs: flush on shutdown (#3009)
• 6d99e1c util: prevent read buffer from being swapped during a read_poll (#2993)
• Additional commits viewable in compare view

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[dependabot-preview]

Superseded by #36.