UICollectionViewDataSourcePrefetching & UICollectionViewDiffableDataSource

Code Block swift
    func viewDidLoad()
        ....
        collectionView.prefetchDataSource = self
        collectionView.isPrefetchingEnabled = true
    }
extension ViewController: UICollectionViewDataSourcePrefetching {
    func collectionView(_ collectionView: UICollectionView, prefetchItemsAt indexPaths: [IndexPath]) {
        let urls: [URL] = indexPaths.compactMap { indexPath in
            guard let displayableItem = dataSource.itemIdentifier(for: indexPath),
                let itemViewModel = displayableItem.item as? ViewModel,
                let image = itemViewModel.firstImageURL else {
                    return nil
            }
            return image
        }
        ATHLogging.log.critical("prefetching: \(urls)")
        preheater.startPreheating(with: urls)
    }