anchor.diff:  
     bool desc;
     List<Pair<T>> list, mainList;
  +  SelectableItem _selected;
   
     FetchType _fetchType;
     int _fetchTs = 0;
  
positive.code:     $state.loading = true;
      return true;
    }
  }
  
  
negative.code:   int ts;
  }
  
  abstract class SelectableItem {
    int get index;
    void reset();
  }
  
  abstract class Pair<T> {
    T orig;
    T copy;
  