Fix disconnects when there is a large send queue

The message delivery confirmation didn't send the PING immediately, so the remaining send queue blocked it, which would then cause the confirmation to fail, all messages to be requeued, and the connection to be closed.

http2irc.py

@@ -586,7 +586,7 @@ class IRCClientProtocol(asyncio.Protocol):
 				continue
 			self.logger.debug('Trying to confirm message delivery')
 			self.pongReceivedEvent.clear()
-			self.send(b'PING :42')
+			self._direct_send(b'PING :42')
 			await wait_cancel_pending({asyncio.create_task(self.pongReceivedEvent.wait())}, return_when = asyncio.FIRST_COMPLETED, timeout = 5)
 			self.logger.debug(f'Message delivery successful: {self.pongReceivedEvent.is_set()}')
 			if not self.pongReceivedEvent.is_set():