Start the Gateway Search Request and return the address information

        :rtype: (string,int)
        :return: a tuple(string(IP),int(Port) when found or None when
            timeout occurs

def start_search(self):
        """
        Start the Gateway Search Request and return the address information

        :rtype: (string,int)
        :return: a tuple(string(IP),int(Port) when found or None when
            timeout occurs
        """

        self._asyncio_loop = asyncio.get_event_loop()

        # Creating Broadcast Receiver
        coroutine_listen = self._asyncio_loop.create_datagram_endpoint(
            lambda: self.KNXSearchBroadcastReceiverProtocol(
                self._process_response,
                self._timeout_handling,
                self._timeout,
                self._asyncio_loop
            ), local_addr=(self._broadcast_ip_address, 0)
        )
        self._listener_transport, listener_protocol = \
            self._asyncio_loop.run_until_complete(coroutine_listen)

        # We are ready to fire the broadcast message
        coroutine_broadcaster = self._asyncio_loop.create_datagram_endpoint(
            lambda: self.KNXSearchBroadcastProtocol(
                self._asyncio_loop,
                self._listener_transport.get_extra_info('sockname')
                [1]),
            remote_addr=(self._broadcast_address, self._broadcast_port))

        self._broadcaster_transport, broadcast_protocol = \
            self._asyncio_loop.run_until_complete(coroutine_broadcaster)
        # Waiting for all Broadcast receive or timeout
        self._asyncio_loop.run_forever()

        # Got Response or Timeout
        if self._resolved_gateway_ip_address is None and \
           self._resolved_gateway_ip_port is None:
            LOGGER.debug("Gateway not found!")
            return None
        else:
            LOGGER.debug("Gateway found at %s:%s",
                         self._resolved_gateway_ip_address,
                         self._resolved_gateway_ip_port)

            return self._resolved_gateway_ip_address, \
                self._resolved_gateway_ip_port