anchor.diff:    DateTime startTime;
     Timer timeoutTimer;
     int pid;
  -  List<int> stdout = <int>[];
  -  List<int> stderr = <int>[];
  +  OutputLog stdout = new OutputLog();
  +  OutputLog stderr = new OutputLog();
     bool compilationSkipped = false;
     Completer<CommandOutput> completer;
   
  
positive.code:   }
  
    Command _getUniqueCommand(Command command) {
      // All Command classes have hashCode/operator==, so we check if this command
      // has already been build, if so we return the cached one, otherwise we
      // store the one given as [command] argument.
      var cachedCommand = _cachedCommands[command];
      if (cachedCommand != null) {
  
negative.code:           _stderrSubscription.pause();
            _stderrCompleter.complete(null);
          } else {
            _testStderr.add(encodeUtf8(line));
            _testStderr.add("\n".codeUnits);
          }
        });
        _stderrSubscription.pause();
  