Completing unnecessary tasks at user-disconnect

[Vibhu-Agarwal]

Hedwig/messaging.py

Lines 76 to 79 in 1e2cbf1

	await asyncio.gather(*self.save_msg_in_db_tasks)
	self.save_msg_in_db_tasks.clear()
	for task in self.reader_tasks:
	task.done()

Here, only user is disconnecting. Not even the chat-room is shutting down.
Here, save_msg_in_db_tasks and reader_tasks, both store data for all users there are, and so this is processing for all users' data, not just the one which is disconnecting.

Efficient Solution: Process only those tasks which are created by the disconnecting user