release 5.2.0

Features:
 - issue #158: set pending futures to BrokenProcessPool error
   when ProcessPool internal errors occur.

Fixes:
 - Cleanup resources when terminating pool's processes via SIGTERM.

release 5.1.3

Fixes:
 - issue #152: fix crash when scheduling non copy-able functions

release 5.1.2

Fixes:
 - issue #101: allow `atexit.register` callbacks on pool shutdown
 - Fix deadlock with `waitforthreads` function
 - Fix bug causing threads to crash when using `waitforthreads`
   function

release 5.1.1

Fixes:
 - issue #146: fix pool hanging on pickle errors.
 - issue #147: fix pool hanging when futures are cancelled while large
   amount of data is being transferred.

release 5.1.0

Features:

• issue #140: expose internal constants to allow changing default
  timeouts and polling intervals.
• issue #141: add PID of expired process to ProcessExpired
  exception. Credits: @rsiemens
• Add pool decorators parameter allowing to provide a PebblePool
  as executor for the decorated functions.

Fixes:

• issue #137: reset SIGTERM default handler to child processes.
• Include concurrent and asynchronous modules as top-level
  packages.

Improvements:

• Improve type hinting logic. Credits: @emiliadecaudin , @ccazabon
• Refactor internal logic: remove code duplication.

release 5.0.7

Fixes:
 - issue #96: handle race condition under different interpreters
 - issue #125: handle frozen classes as exceptions
 - issue #127: handle unexpected errors when reading from pipe in
               process decorators
 - issue #128: allow different context from `multiprocessing` ones

release 5.0.6

Fixes:
 - issue #124: handle `BaseException` in pools' workers

release 5.0.5

Fixes:
 - issue #123: do not raise exception when returned from workers

Improvements:
 - issue #122: slightly improve type hints

release 5.0.4

Improvements:
 - issue #122: add type hints to decorator functions

release 5.0.3

Fixes:
 - issue #111: reinstate `Pool.schedule` function in place of
   `Pool.submit`.