Tokio v1.38.0

This release marks the beginning of stabilization for runtime metrics. It
stabilizes RuntimeMetrics::worker_count. Future releases will continue to
stabilize more metrics.

Added

• fs: add File::create_new (#6573)
• io: add copy_bidirectional_with_sizes (#6500)
• io: implement AsyncBufRead for Join (#6449)
• net: add Apple visionOS support (#6465)
• net: implement Clone for NamedPipeInfo (#6586)
• net: support QNX OS (#6421)
• sync: add Notify::notify_last (#6520)
• sync: add mpsc::Receiver::{capacity,max_capacity} (#6511)
• sync: add split method to the semaphore permit (#6472, #6478)
• task: add tokio::task::join_set::Builder::spawn_blocking (#6578)
• wasm: support rt-multi-thread with wasm32-wasi-preview1-threads (#6510)

Changed

• macros: make #[tokio::test] append #[test] at the end of the attribute list (#6497)
• metrics: fix blocking_threads count (#6551)
• metrics: stabilize RuntimeMetrics::worker_count (#6556)
• runtime: move task out of the lifo_slot in block_in_place (#6596)
• runtime: panic if global_queue_interval is zero (#6445)
• sync: always drop message in destructor for oneshot receiver (#6558)
• sync: instrument Semaphore for task dumps (#6499)
• sync: use FIFO ordering when waking batches of wakers (#6521)
• task: make LocalKey::get work with Clone types (#6433)
• tests: update nix and mio-aio dev-dependencies (#6552)
• time: clean up implementation (#6517)
• time: lazily init timers on first poll (#6512)
• time: remove the true_when field in TimerShared (#6563)
• time: use sharding for timer implementation (#6534)

Fixed

• taskdump: allow building taskdump docs on non-unix machines (#6564)
• time: check for overflow in Interval::poll_tick (#6487)
• sync: fix incorrect is_empty on mpsc block boundaries (#6603)

Documented

• fs: rewrite file system docs (#6467)
• io: fix stdin documentation (#6581)
• io: fix obsolete reference in ReadHalf::unsplit() documentation (#6498)
• macros: render more comprehensible documentation for select! (#6468)
• net: add missing types to module docs (#6482)
• net: fix misleading NamedPipeServer example (#6590)
• sync: add examples for SemaphorePermit, OwnedSemaphorePermit (#6477)
• sync: document that Barrier::wait is not cancel safe (#6494)
• sync: explain relation between watch::Sender::{subscribe,closed} (#6490)
• task: clarify that you can't abort spawn_blocking tasks (#6571)
• task: fix a typo in doc of LocalSet::run_until (#6599)
• time: fix test-util requirement for pause and resume in docs (#6503)