docs: private static EventListener toEntryListener(Object implementation) {
          if (implementation instanceof EntryListener) {
              return (EventListener) implementation;
          }
  
          if (implementation instanceof MapListener) {
              return new MapListenerToEntryListenerAdapter((MapListener) implementation);
          }
  
          throw new IllegalArgumentException(implementation + " is not an expected EventListener implementation."
                  + " A valid one has to be an implementation of EntryListener or MapListener");
  
      }