Changelog:
===========
Added send_packet() method
Fixed race condition when lots of connections are ended at the same time #328
Workaround for strange memory leak in Eventlet's Thread class #328
Use daemon threads for background tasks in threading mode
Upgrade to pypy-3.9 in unit tests
Fix double close of websockets in ASGI adapter #327
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
