Double confirmation for transport close.
        Some broken ssl servers may leave socket open without proper close.

def _cleanup_closed(self) -> None:
        """Double confirmation for transport close.
        Some broken ssl servers may leave socket open without proper close.
        """
        if self._cleanup_closed_handle:
            self._cleanup_closed_handle.cancel()

        for transport in self._cleanup_closed_transports:
            if transport is not None:
                transport.abort()

        self._cleanup_closed_transports = []

        if not self._cleanup_closed_disabled:
            self._cleanup_closed_handle = helpers.weakref_handle(
                self, '_cleanup_closed',
                self._cleanup_closed_period, self._loop)