Tokio v0.2.22

This release introduces initial support for tracing instrumentation within the Tokio
runtime, enabled by the "tracing" feature flag. In addition, it contains a number of bug
fixes and API additions.

Fixes

• docs: misc improvements (#2572, #2658, #2663, #2656, #2647, #2630, #2487, #2621,
  #2624, #2600, #2623, #2622, #2577, #2569, #2589, #2575, #2540, #2564, #2567,
  #2520, #2521, #2493)
• rt: allow calls to block_on inside calls to block_in_place that are
  themselves inside block_on (#2645)
• net: fix non-portable behavior when dropping TcpStream OwnedWriteHalf (#2597)
• io: improve stack usage by allocating large buffers on directly on the heap
  (#2634)
• io: fix unsound pin projection in AsyncReadExt::read_buf and
  AsyncWriteExt::write_buf (#2612)
• io: fix unnecessary zeroing for AsyncRead implementors (#2525)
• io: Fix BufReader not correctly forwarding poll_write_buf (#2654)
• io: fix panic in AsyncReadExt::read_line (#2541)

Changes

• coop: returning Poll::Pending no longer decrements the task budget (#2549)

Added

• io: little-endian variants of AsyncReadExt and AsyncWriteExt methods
  (#1915)
• task: add tracing instrumentation to spawned tasks (#2655)
• sync: allow unsized types in Mutex and RwLock (via default constructors)
  (#2615)
• net: add ToSocketAddrs implementation for &[SocketAddr] (#2604)
• fs: add OpenOptionsExt for OpenOptions (#2515)
• fs: add DirBuilder (#2524)

Signed-off-by: Eliza Weisman [email protected]