[3.9] bpo-39010: Fix errors logged on proactor loop restart (GH-22017) by miss-islington · Pull Request #22034 · python/cpython

Stopping and restarting a proactor event loop on windows can lead to
spurious errors logged (ConnectionResetError while reading from the
self pipe). This fixes the issue by ensuring that we don't attempt
to start multiple copies of the self-pipe reading loop.
(cherry picked from commit ea5a636)

Co-authored-by: Ben Darnell ben@bendarnell.com

https://bugs.python.org/issue39010

Automerge-Triggered-By: @1st1