Deadlock following timeout

[NitzanBoden]

When attempting to send notifications with timeout, first timeout causes a deadlock to the sender making future request wait for a lock endlessly.

Example:

My code calls send_notifications with timeout:
response = await asyncio.wait_for(self.client.send_notification(request), timeout)

After multiple successful sends I got a timeout with:

Traceback (most recent call last):
  File \"/usr/local/lib/python3.10/site-packages/aioapns/client.py\", line 58, in send_notification
    response = await self.pool.send_notification(request)
  File \"/usr/local/lib/python3.10/site-packages/aioapns/connection.py\", line 387, in send_notification
    connection = await self.acquire()
  File \"/usr/local/lib/python3.10/site-packages/aioapns/connection.py\", line 358, in acquire
    connection = await self.create_connection()
  File \"/usr/local/lib/python3.10/site-packages/aioapns/connection.py\", line 501, in create_connection
    _, protocol = await self.loop.create_connection(
  File \"/usr/local/lib/python3.10/asyncio/base_events.py\", line 1089, in create_connection
    transport, protocol = await self._create_connection_transport(
  File \"/usr/local/lib/python3.10/asyncio/base_events.py\", line 1119, in _create_connection_transport
    await waiter
asyncio.exceptions.CancelledError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File \"/usr/local/lib/python3.10/asyncio/tasks.py\", line 456, in wait_for
    return fut.result()
asyncio.exceptions.CancelledError

but since it exits without releasing the lock it acquires - all future requests gets stuck waiting for the same lock:

Traceback (most recent call last):
  File \"/usr/local/lib/python3.10/site-packages/aioapns/client.py\", line 58, in send_notification
    response = await self.pool.send_notification(request)
  File \"/usr/local/lib/python3.10/site-packages/aioapns/connection.py\", line 387, in send_notification
    connection = await self.acquire()
  File \"/usr/local/lib/python3.10/site-packages/aioapns/connection.py\", line 351, in acquire
    await self._lock.acquire()
  File \"/usr/local/lib/python3.10/asyncio/locks.py\", line 114, in acquire
    await fut
asyncio.exceptions.CancelledError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File \"/usr/local/lib/python3.10/asyncio/tasks.py\", line 456, in wait_for
    return fut.result()
asyncio.exceptions.CancelledError

Was there a reason you chose to not use a context manager with this lock? If not is it possible to change it to use one to avoid this situation?