anchor.diff:      _completed.add(uri);
   
       if(_completed.length == _urlList.length) {
  +      _state = StateLoaded;
         _loadedEvent.fireEvent(EventArgs.empty);
  +    } else {
  +      _progressEvent.fireEvent(EventArgs.empty);
       }
     }
   
  
positive.code: 
    ResourceLoader(this._urlList) :
      _loadedEvent= new EventHandle<EventArgs>(),
      _resources = new Map<String, T>(),
      _completed = new Set<String>();
  
    String get state => _state;
  
    EventRoot get loaded => _loadedEvent;
  
    T getResource(String url) => _resources[url];
  
  
negative.code: 
    final List<String> _urlList;
    final EventHandle<EventArgs> _loadedEvent;
    final EventHandle<EventArgs> _progressEvent;
    final Map<String, T> _resources;
    final Set<String> _completed;
  
  