                         // double check
                         if indexPaths.count == (strongSelf.messages.count - _lastTimeMessagesCount) {
                             strongSelf.conversationCollectionView.insertItemsAtIndexPaths(indexPaths)
+
                         } else {
                             strongSelf.conversationCollectionView.reloadSections(NSIndexSet(index: Section.Message.rawValue))
                             strongSelf.lastTimeMessagesCount = strongSelf.messages.count
-                            println("double check failed!")
+                            println("double check failed! \(strongSelf.messages.count), \(_lastTimeMessagesCount)")
                         }
 
                     }, completion: nil)


        // 异常：两种计数不相等，治标：reload，避免插入
        if let messageIDs = messageIDs {
            if newMessagesCount != messageIDs.count {
                reloadConversationCollectionView()
                println("newMessagesCount != messageIDs.count")
                #if DEBUG
                    YepAlert.alertSorry(message: "请截屏报告!\nnewMessagesCount: \(newMessagesCount)\nmessageIDs.count: \(messageIDs.count)", inViewController: self)
                #endif

                    // double check
                    if indexPaths.count == (strongSelf.messages.count - _lastTimeMessagesCount) {
                        strongSelf.conversationCollectionView.insertItemsAtIndexPaths(indexPaths)

                    } else {
                        strongSelf.conversationCollectionView.reloadSections(NSIndexSet(index: Section.Message.rawValue))
                        strongSelf.lastTimeMessagesCount = strongSelf.messages.count
                        println("double check failed! \(strongSelf.messages.count), \(_lastTimeMessagesCount)")
                    }

                }, completion: nil)
