应用NSDiffableDataSourceSnapshot时，在ViewController跳转中拉动以刷新UICollectionView

class YourViewController: UIViewController, UICollectionViewDelegate {
    // 声明你的UICollectionView和NSDiffableDataSourceSnapshot
    private var collectionView: UICollectionView!
    private var dataSource: UICollectionViewDiffableDataSource<Section, Item>!
    private var snapshot: NSDiffableDataSourceSnapshot<Section, Item>!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置你的UICollectionView和NSDiffableDataSourceSnapshot
        
        // 设置UICollectionView的delegate为self
        collectionView.delegate = self
    }
    
    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
        // 判断是否到达了底部
        let isReachingBottom = scrollView.contentOffset.y >= (scrollView.contentSize.height - scrollView.frame.size.height)
        
        // 判断是否到达了顶部
        let isReachingTop = scrollView.contentOffset.y <= 0
        
        if isReachingBottom || isReachingTop {
            // 执行刷新操作，比如重新加载数据、请求新的数据等
            
            // 更新NSDiffableDataSourceSnapshot中的数据
            // ...
            
            // 调用apply(_:animatingDifferences:)方法来更新UICollectionView的显示
            dataSource.apply(snapshot, animatingDifferences: true)
        }
    }
}