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    func loadMoreChatMessages() {
        self.showLoadEarlierMessagesHeader = false
        page += 1
        let bottomOffset = self.collectionView.contentSize.height - self.collectionView.contentOffset.y
        
        CATransaction.begin()
        CATransaction.setDisableActions(true)

        fetchChatData(false) {[unowned self] (_) in
            if !self.historyMessages.isEmpty {
                self.collectionView.performBatchUpdates({
                    

                    self.collectionView.performBatchUpdates({
                        
                        //let lastIdx = self.messagesCountIndexes
                        var indexPaths = [IndexPath]()
                        //create indexs
                        for i in 0..<self.historyMessages.count {
                            indexPaths.append(IndexPath(row: i, section: 0))
                        }
                        // insert messages and update data source.
                        self.incomingMessagesWithMedia.insert(contentsOf: self.historyMessages, at: 0)
                        
                        self.collectionView.insertItems(at: indexPaths)
                        
                        // invalidate layout
                        
//                        self.collectionView.collectionViewLayout.invalidateLayout(with: JSQMessagesCollectionViewFlowLayoutInvalidationContext())
                        
                    }, completion: { (finished) in
//                        self.finishReceivingMessage(animated: false)
                        self.collectionView.reloadData()
//                        self.collectionView.layoutIfNeeded()
                        //scroll back to current position
                        self.collectionView.contentOffset = CGPoint(x: 0, y: self.collectionView.contentSize.height - bottomOffset)
//                        let lastIdx = IndexPath(row: self.historyMessages.count, section: 0)
//                        self.scroll(to: lastIdx, animated: true)
                        self.historyMessages.removeAll()
                        self.showLoadEarlierMessagesHeader = true
                    })
                })
            }
        }
        CATransaction.commit()
    }