anchor.diff:    parser
       ..addOption(
         argTryPorts,
  -      defaultsTo: '1',
  +      defaultsTo: defaultTryPorts.toString(),
         valueHelp: 'count',
         help: 'The number of ascending ports to try binding to before failing '
             'with an error. ',
  
positive.code:   final port = args[argPort] != null ? int.tryParse(args[argPort]) ?? 0 : 0;
    final bool headlessMode = args[argHeadlessMode];
    final bool debugMode = args[argDebugMode];
    final numPortsToTry =
        args[argTryPorts] != null ? int.tryParse(args[argTryPorts]) ?? 1 : 1;
    final bool verboseMode = args[argVerbose];
    final String hostname = args[argHost];
  
  
negative.code:   bool verboseMode = false,
    String hostname,
    int port = 0,
    int numPortsToTry = defaultTryPorts,
    shelf.Handler handler,
    String serviceProtocolUri,
    String profileFilename,
  