service_advertiser.dart

import 'dart:io'
    show RawDatagramSocket, RawSocketEvent, InternetAddress, Datagram;
import 'dart:convert' show utf8;

main() =>
    // UDP server
    RawDatagramSocket.bind(InternetAddress.anyIPv4, 8000)
        .then((datagramSocket) {
      datagramSocket.readEventsEnabled = true;
      datagramSocket.listen((RawSocketEvent event) {
        if (event == RawSocketEvent.read) {
          Datagram dg = datagramSocket.receive();
          if (dg != null) {
            datagramSocket.send(dg.data, dg.address, dg.port);
            print('${dg.address}:${dg.port} -- ${utf8.decode(dg.data)}');
          }
        }
      });
    });