anchor.diff:    void _sync(StatefulComponent old, dynamic slot) {
       if (old == null) {
         if (!_isStateInitialized) {
  +        assert(mounted);
  +        assert(!_wasMounted);
           initState();
           _isStateInitialized = true;
         }
  
positive.code: 
  // TODO(ianh): Move this to Widget
  void _endSyncPhase() {
    Widget._currentGeneration += 1;
    Widget._notifyMountStatusChanged();
  }
  
  // TODO(ianh): Move this to Component
  
negative.code:     details.add('hashCode=$hashCode');
      details.add(mounted ? 'mounted' : 'not mounted');
      if (_generation != _currentGeneration) {
        if (_generation == 0) {
          details.add('never synced');
        } else {
          int delta = _generation - _currentGeneration;
          String sign = delta < 0 ? '' : '+';
          details.add('gen$sign$delta');
        }
      }
    }
  
  