在UICollectionViewCompositionalLayout / UICollectionViewDiffableDataSource的两个不同部分显示相同的对象

import UIKit

struct Item: Hashable {
    let id: UUID
    let name: String
}

class ViewController: UIViewController {
    var collectionView: UICollectionView!
    var dataSource: UICollectionViewDiffableDataSource<Section, Item>!

    enum Section {
        case main
        case secondary
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let layout = createLayout()
        collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: layout)
        view.addSubview(collectionView)
        
        configureDataSource()
        updateData()
    }

    func createLayout() -> UICollectionViewCompositionalLayout {
        let itemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .estimated(44))
        let item = NSCollectionLayoutItem(layoutSize: itemSize)
        
        let section1 = NSCollectionLayoutSection(group: NSCollectionLayoutGroup.horizontal(layoutSize: itemSize, subitems: [item]))
        section1.orthogonalScrollingBehavior = .groupPaging
        
        let section2 = NSCollectionLayoutSection(group: NSCollectionLayoutGroup.horizontal(layoutSize: itemSize, subitems: [item]))
        section2.orthogonalScrollingBehavior = .groupPaging
        
        let config = UICollectionViewCompositionalLayoutConfiguration()
        config.scrollDirection = .vertical
        
        return UICollectionViewCompositionalLayout(section: [section1, section2], configuration: config)
    }

    func configureDataSource() {
        dataSource = UICollectionViewDiffableDataSource<Section, Item>(collectionView: collectionView) { (collectionView, indexPath, item) -> UICollectionViewCell? in
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
            cell.textLabel?.text = item.name
            return cell
        }
    }

    func updateData() {
        var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
        snapshot.appendSections([.main, .secondary])
        
        let items = [
            Item(id: UUID(), name: "Item 1"),
            Item(id: UUID(), name: "Item 2"),
            Item(id: UUID(), name: "Item 3")
        ]
        
        snapshot.appendItems(items, toSection: .main)
        snapshot.appendItems(items, toSection: .secondary)
        
        dataSource.apply(snapshot, animatingDifferences: true)
    }
}