anchor.diff:      var fileExists = new File(path).existsSync();
       var dirExists = new Directory(path).existsSync();
   
  +    if (_runningOnBuildbot) {
  +      print("file existed: $fileExisted");
  +      print("dir existed: $dirExisted");
  +      print("file exists: $fileExists");
  +      print("dir exists: $dirExists");
  +    }
  +
       var events = [];
       if (fileExisted) {
         if (fileExists) {
  
positive.code:       if (entity is! Directory) _files.add(entity.path);
      },
          onError: _emitError,
          onDone: _readyCompleter.complete,
          cancelOnError: true);
    }
  
  
negative.code: 
    /// The callback that's run when [Directory.watch] emits a batch of events.
    void _onBatch(List<FileSystemEvent> batch) {
      if (_runningOnBuildbot) {
        print("======== batch:");
        for (var event in batch) {
          print("  ${_formatEvent(event)}");
        }
  
        print("known files:");
        for (var foo in _files.toSet()) {
          print("  ${p.relative(foo, from: directory)}");
        }
      }
  
      batches++;
  
      _sortEvents(batch).forEach((path, events) {
        var relativePath = p.relative(path, from: directory);
        if (_runningOnBuildbot) {
          print("events for $relativePath:\n");
          for (var event in events) {
            print("  ${_formatEvent(event)}");
          }
        }
  
        var canonicalEvent = _canonicalEvent(events);
        events = canonicalEvent == null ?
            _eventsBasedOnFileSystem(path) : [canonicalEvent];
        if (_runningOnBuildbot) {
          print("canonical event for $relativePath: "
              "${_formatEvent(canonicalEvent)}");
          print("actionable events for $relativePath: "
              "${events.map(_formatEvent)}");
        }
  
        for (var event in events) {
          if (event is FileSystemCreateEvent) {
  