不滚动平滑的UICollectionViewController为大数据加载

I am new to iOS and I'm trying to load data in collectionviewcontroller. Data is loading and scrolling for less data. But scroll get stuck when loading large data. But as data in my collection gets increasing, its scrolling becomes rough and after loading some pages, it becomes very hard to scroll up or down. It is getting stuck.I am new to iOS and I'm trying to load data in