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

        
        case MessageMediaType.ShareFeed.rawValue:
            height = 60
        default:
            height = 20
        }

                        // 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: { [weak self] finished in
