anchor.diff:  }
   
   final ChatAPI = {
  -  'subscribeToFriendStatus': (int id, Function handleStatusChange) => handleStatusChange({'isOnline': id % 2 == 0 ? true : false}),
  +  'subscribeToFriendStatus': (int id, Function handleStatusChange) =>
  +      handleStatusChange({'isOnline': id % 2 == 0 ? true : false}),
     'unsubscribeFromFriendStatus': (int id, Function handleStatusChange) => handleStatusChange({'isOnline': false}),
   };
   
  
positive.code:   void handleStatusChange(Map status) {
      isOnline.set(status['isOnline']);
    }
    
    useEffect(() {
      ChatAPI['subscribeToFriendStatus'](friendID, handleStatusChange);
      return () {
  
negative.code:             'key': 'useStateTest',
            }, []),
            react.h2({'key': 'useDebugValueTestLabel'}, ['useDebugValue Hook Test']),
            FriendListItem({
              'friend': {'id': 1, 'name': 'user 1'}
            }, []),
            FriendListItem({
              'friend': {'id': 2, 'name': 'user 2'}
            }, []),
            FriendListItem({
              'friend': {'id': 3, 'name': 'user 3'}
            }, []),
            FriendListItem({
              'friend': {'id': 4, 'name': 'user 4'}
            }, []),
          ]),
          querySelector('#content'));
    }
  