gh-156920: fix ProactorEventLoop datagram transports drop buffered datagrams on close() and never call connection_lost() - #156921

gh-156920: fix ProactorEventLoop datagram transports drop buffered datagrams on close() and never call connection_lost()#156921

graingert wants to merge 6 commits into

python:mainpython/cpython:mainfrom

graingert:fix-proactor-close-flushgraingert/cpython:fix-proactor-close-flushCopy head branch name to clipboard