async def disconnect(self) -> None:
        logger.info(
            f"Disconnecting from telnet server at {self.host}:{self.port}..."
        )
        self._running = False
        if self._connection_task:
            self._connection_task.cancel()
            try:
                await self._connection_task
            except asyncio.CancelledError:
                pass  # Expected
            # _manage_connection's finally block should have closed the writer
            # and sent DISCONNECTED, but if the task hadn't started yet when
            # cancelled, the finally block was never entered. Check whether
            # cleanup actually happened and do it ourselves if not.
            if self.writer is not None:
                self.writer.close()
                try:
                    await self.writer.wait_closed()
                except (ConnectionResetError, OSError):
                    pass
                self.writer = None
                self.reader = None
                self.status_changed.send(
                    self, status=TransportStatus.DISCONNECTED
                )
            self._connection_task = None
            return
        if self.writer:
            self.writer.close()
            try:
                await self.writer.wait_closed()
            except (ConnectionResetError, OSError):
                pass  # The other end might have already closed it.
        self.writer = None
        self.reader = None
        self.status_changed.send(self, status=TransportStatus.DISCONNECTED)
        logger.info(f"Disconnected from {self.host}:{self.port}.")