anchor.diff:        _totalEntitiesCountController.stream;
   
     @override
  -  CountGetter entitiesOnPageCount = () => -1;
  +  CountGetter entitiesOnPageCount = _noCountGetter;
   
     @override
     IsIndeterminate isIndeterminate;
  
positive.code: 
    bool _allSelected = false;
  
    CountGetter _totalEntitiesCount = () => -1;
  
    @override
    CountGetter get totalEntitiesCount => _totalEntitiesCount;
  
    @override
    set totalEntitiesCount(CountGetter value) {
  
negative.code: import 'selection_model.dart';
  
  typedef bool IsIndeterminate(var entity);
  
  /// Count getter to return when there is no valid count
  final CountGetter _noCountGetter = () => -1;
  
  /// Selection model interface that is meant to be used with the table view
  /// component.
  