code: public static void fire(final HasSummernoteKeyDownHandlers source, NativeEvent nativeEvent) {
          if (TYPE != null) {
              SummernoteKeyDownEvent event = new SummernoteKeyDownEvent(nativeEvent);
              source.fireEvent(event);
          }
      }
docs: Fires a summernote key down event on all registered handlers in the handler
  manager. If no such handlers exist, this method will do nothing.
  
  @param source the source of the handlers
  @param nativeEvent native key down event