anchor.diff:      @required this.clearSearchField,
       this.keyEventsToPropagate = const {},
       this.supportClearField = false,
  -    this.closeHandler,
     });
   
     final AutoCompleteSearchControllerMixin controller;
  
positive.code:   FocusNode _searchFieldFocusNode;
    FocusNode _rawKeyboardFocusNode;
    SelectAutoComplete _onSelection;
    void Function() _closeHandler;
  
    FocusNode get searchFieldFocusNode => _searchFieldFocusNode;
  
  
negative.code:     super.dispose();
      searchTextFieldController?.dispose();
    }
  
    /// Hookup up TextField (search field) to the auto-complete overlay
    /// pop-up.
  