报这个错误。

The collection view's data source returned a supplementary view that is in the reuse queue. Supplementary views must be retrieved by calling dequeueConfiguredReusableSupplementaryViewWithRegistration:forIndexPath: or -dequeueReusableSupplementaryViewOfKind:withReuseIdentifier:forIndexPath:.

解决方法： 注释掉（WFCUMessageListViewController.m）中的下面这个方法（似乎没有什么影响）：

• (UICollectionReusableView ) collectionView:(UICollectionView )collectionView viewForSupplementaryElementOfKind:(NSString )kind atIndexPath:(NSIndexPath )indexPath