internal void DisposeIndexer(CollectionIndexer indexer)
 {
     lock (this) {
         ServiceManager.DBusServiceManager.UnregisterObject(indexer);
         open_indexers--;
     }
 }
 internal void DisposeIndexer(CollectionIndexer indexer)
 {
     lock (this) {
         ServiceManager.DBusServiceManager.UnregisterObject (indexer);
         open_indexers--;
     }
 }