This method will be called after `connect` is called.
        After this method finishes, the writer will be drained.

        Subclasses should make use of this if they need to send
        data to Telegram to indicate which connection mode will
        be used.

def _init_conn(self):
        """
        This method will be called after `connect` is called.
        After this method finishes, the writer will be drained.

        Subclasses should make use of this if they need to send
        data to Telegram to indicate which connection mode will
        be used.
        """
        if self._codec.tag:
            self._writer.write(self._codec.tag)