How can you ensure botframework's (MSTeams) messages are sent successfully?

Question

I'm sending messages using turn_context.send_message as follows:

# Generic bot handler with two functions:
# 1. Send Message (in theory, the problem lies here) tries to send a message, returns False if it doesn't 
# finish within two seconds, and returns True if it's successful.
# 2. Persistent Message remains in a loop so long as Send Message is failing, until it eventually succeeds.
class MyBot(ActivityHandler):

    @staticmethod
    # The aim - if the message isn't sent in two seconds, kill this attempt and start over.
    async def send_message(message, turn_context):
        # This line sometimes hangs the ENTIRE thread and prevents all the following code from being read.
        task = asyncio.create_task(turn_context.send_activity(message))
        # This sleep is never reached.
        await asyncio.sleep(2)
        if task.done():
            return True
        task.cancel()
        return False

    async def persistent_message(self, message, turn_context):
        x = await self.send_message(message, turn_context)
        while not x:
            x = await self.send_message(message, turn_context)
        return x

    async def on_message_activity(self, turn_context: TurnContext):
        # This calls persistent_message, aiming to send "pong" to the user, using the context.
        self.persistent_message("pong!", turn_context)

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Issue:

When using wait_for, wait, create_task/task.cancel, etc, all of these functions fail to kill the task so that the send_message coro can end successfully.

For wait_for and wait, I'm assuming this behavior is because these methods must wait for the coro to get cancelled, but doesn't task.cancel immediately kill a running task?

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Questions:

1. Is there an easier way to ensure the messages that the bot is supposed to send are actually sent?
2. Why does this code block behave this way, and how can it be circumvented to ensure that the messages are sent?

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P.S: The code sends no exceptions - it simply doesn't send the messages. wait and wait_for did not work either.