AssistSuggestionItemSelectedCallback typedef
        AssistSuggestionItemSelectedCallback =
     void Function(bool selected, int messageIndex, AssistMessageSuggestion suggestion, int suggestionIndex)
    
    
Callback that get invoked when the toolbar item got selected.
Implementation
typedef AssistSuggestionItemSelectedCallback =
    void Function(
      bool selected,
      int messageIndex,
      AssistMessageSuggestion suggestion,
      int suggestionIndex,
    );