@Override
 public void packageSourceAdded(SourceDeltaEvent event) {
   if (shouldForward(event)) {
     listener.packageSourceAdded(event);
   } else {
     IResource resource = event.getResource();
     if (resource != null) {
       markerManager.clearMarkers(resource);
     }
   }
 }
 public IgnoreResourceFilter() {
   this(DartCore.getIgnoreManager(), AnalysisMarkerManager.getInstance());
 }