anchor.diff:    void changeFile(String path) {
       _filesToVerifyUnlinkedSignature.add(path);
       _filesToAnalyze.add(path);
  -    _hasWorkStreamController.add('do it!');
  +    _hasWork.notify();
     }
   
     /**
  
positive.code:     _requestedFiles
          .putIfAbsent(path, () => <Completer<AnalysisResult>>[])
          .add(completer);
      _hasWorkStreamController.add(path);
      return completer.future;
    }
  
  
negative.code:   final _dependencySignatureMap = <Uri, String>{};
  
    /**
     * The monitor that is signalled when there is work to do.
     */
    final _Monitor _hasWork = new _Monitor();
  
    AnalysisDriver(this._logger, this._resourceProvider, this._byteStore,
        this._contentCache, this._sourceFactory, this._analysisOptions) {
  