anchor.diff:    var parser = new ArgParser();
     parser.addOption('port', abbr: 'p', defaultsTo: '8080');
     parser.addOption('dart-sdk');
  +  parser.addFlag('discovery');
  +  parser.addOption('server-url', defaultsTo: 'http://localhost');
   
     var result = parser.parse(args);
     var port = int.parse(result['port'], onError: (val) {
  
positive.code:       endpointsServer.server = server;
        return endpointsServer;
      });
    }
  
    final int port;
  
negative.code:         "Could not locate the SDK; "
          "please start the server with the '--dart-sdk' option.");
      exit(1);
    }
  
    if (result['discovery']) {
      var serverUrl = result['server-url'];
      EndpointsServer.generateDiscovery(sdkDir.path, serverUrl).then((doc) {
        print(doc);
        exit(0);
      });
      return;
    }
  
    Logger.root.onRecord.listen((r) => print(r));
  