How to use the pychromecast.cast_channel_pb2.CastMessage function in PyChromecast

# data is a dict that will be converted to json
        # wait_for_response only works if we have a request id

        # If channel is not open yet, connect to it.
        self._ensure_channel_connected(destination_id)

        request_id = None
        if not no_add_request_id:
            request_id = self._gen_request_id()
            data[REQUEST_ID] = request_id

        if inc_session_id:
            data[SESSION_ID] = self.session_id

        # pylint: disable=no-member
        msg = cast_channel_pb2.CastMessage()

        msg.protocol_version = msg.CASTV2_1_0
        msg.source_id = self.source_id
        msg.destination_id = destination_id
        msg.payload_type = cast_channel_pb2.CastMessage.STRING
        msg.namespace = namespace
        msg.payload_utf8 = _json_to_payload(data)

        # prepend message with Big-Endian 4 byte payload size
        be_size = pack(">I", msg.ByteSize())

        # Log all messages except heartbeat
        if msg.namespace != NS_HEARTBEAT:
            self.logger.debug(
                "[%s:%s] Sending: %s",
                self.fn or self.host,

def _read_message(self):
        """ Reads a message from the socket and converts it to a message. """
        # first 4 bytes is Big-Endian payload length
        payload_info = self._read_bytes_from_socket(4)
        read_len = unpack(">I", payload_info)[0]

        # now read the payload
        payload = self._read_bytes_from_socket(read_len)

        # pylint: disable=no-member
        message = cast_channel_pb2.CastMessage()
        message.ParseFromString(payload)

        return message

request_id = None
        if not no_add_request_id:
            request_id = self._gen_request_id()
            data[REQUEST_ID] = request_id

        if inc_session_id:
            data[SESSION_ID] = self.session_id

        # pylint: disable=no-member
        msg = cast_channel_pb2.CastMessage()

        msg.protocol_version = msg.CASTV2_1_0
        msg.source_id = self.source_id
        msg.destination_id = destination_id
        msg.payload_type = cast_channel_pb2.CastMessage.STRING
        msg.namespace = namespace
        msg.payload_utf8 = _json_to_payload(data)

        # prepend message with Big-Endian 4 byte payload size
        be_size = pack(">I", msg.ByteSize())

        # Log all messages except heartbeat
        if msg.namespace != NS_HEARTBEAT:
            self.logger.debug(
                "[%s:%s] Sending: %s",
                self.fn or self.host,
                self.port,
                _message_to_string(msg, data),
            )

        if not force and self.stop.is_set():