anchor.diff:      details.add('hashCode=$hashCode');
       details.add(mounted ? 'mounted' : 'not mounted');
       if (_generation != _currentGeneration) {
  -      int delta = _generation - _currentGeneration;
  -      String sign = delta < 0 ? '' : '+';
  -      details.add('gen$sign$delta');
  +      if (_generation == 0) {
  +        details.add('never synced');
  +      } else {
  +        int delta = _generation - _currentGeneration;
  +        String sign = delta < 0 ? '' : '+';
  +        details.add('gen$sign$delta');
  +      }
       }
     }
   
  
positive.code:   static void _notifyListeners() {
      assert(!_inBuildDirtyComponents);
      assert(!Widget._notifyingMountStatus);
      assert(_debugDuplicates.isEmpty);
      if (_syncedKeys.isEmpty && _removedKeys.isEmpty)
        return;
      try {
  
negative.code: 
  void _debugReportException(String context, dynamic exception, StackTrace stack) {
    print('------------------------------------------------------------------------');
    'Exception caught while $context'.split('\n').forEach(print);
    print('$exception');
    print('Stack trace:');
    '$stack'.split('\n').forEach(print);
  