def METHOD_NAME(self) -> Set[asyncio.Task]:
    """Close all open connections."""
    tasks = set()
    if self._feedback_task:
        self._feedback_task.cancel()
        tasks.add(self._feedback_task)
        self._feedback_task = None
    if self.connection:
        self.connection.close()
        self.connection = None
    for channel in self._channels:
        channel.close()
    return tasks