Send a message to a client.

def _emit_internal(self, sid, event, data, namespace=None, id=None):
        """Send a message to a client."""
        if six.PY2 and not self.binary:
            binary = False  # pragma: nocover
        else:
            binary = None
        # tuples are expanded to multiple arguments, everything else is sent
        # as a single argument
        if isinstance(data, tuple):
            data = list(data)
        else:
            data = [data]
        self._send_packet(sid, packet.Packet(packet.EVENT, namespace=namespace,
                                             data=[event] + data, id=id,
                                             binary=binary))