anchor.diff:        oldChild = old._child;
       }
   
  -    _isBuilding = true;
  +    String _debugPreviousComponent;
  +    assert(() {
  +      _debugIsBuilding = true;
  +      _debugPreviousComponent = _debugLastComponent;
  +      if (_debugLastComponent != null)
  +        _debugLastComponent = "$_debugPreviousComponent -> ${this.toStringName()}";
  +      else
  +        _debugLastComponent = "Build chain: ${this.toStringName()}";
  +      return true;
  +    });
   
       int lastOrder = _currentOrder;
       _currentOrder = _order;
  
positive.code:       : _order = _currentOrder + 1,
          super._withKey(key);
  
    bool _isBuilding = false;
  
    bool _dirty = true;
  
  
negative.code:   }
  
    void _scheduleBuild() {
      assert(!_debugIsBuilding);
      if (_dirty || !_mounted)
        return;
      _dirty = true;
  