Long story short

Now, await BaseConnector.close() waits until all the connections are closed instead of just sending the closing signal to all the connections. The "Unclosed connection" warnings appeared because some connections required more time to be closed because some protocols (TLS) perform additional steps on connection-close and thus require longer time.

Expected behaviour

BaseConnector.close() exits only when all open connections are closed.

Actual behaviour

BaseConnector.close() does not wait for its all open connections to be closed.

Steps to reproduce

TBD

Your environment

aiohttp 3.5.4