anchor.diff:     * The results of analysis are eventually produced by the [results] stream.
      */
     void addFile(String path) {
  -    // TODO(scheglov) implement
  +    _explicitFiles.add(path);
  +    _filesToAnalyze.add(path);
  +    _hasWorkStreamController.add('do it!');
     }
   
     /**
  
positive.code:    * but does not guarantee this.
     */
    void removeFile(String path) {
      // TODO(scheglov) implement
    }
  }
  
  
negative.code:  * TODO(scheglov) Clean up the list of implicitly analyzed files.
   */
  class AnalysisDriver {
    final PerformanceLog _logger;
  
    /**
     * The resource provider for working with files.
     */
    final ResourceProvider _resourceProvider;
  
    /**
     * The byte storage to get and put serialized data.
     *
     * It can be shared with other [AnalysisDriver]s.
     */
    final ByteStore _byteStore;
  
    /**
     * This [ContentCache] is consulted for a file content before reading
     * the content from the file.
     */
    final ContentCache _contentCache;
  
    /**
     * The [SourceFactory] is used to resolve URIs to paths and restore URIs
  