如何在Swift中的特定索引处显示collectionView

import UIKit

class ViewController: UIViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {
    
    @IBOutlet weak var collectionView: UICollectionView!
    
    let data = ["Item 1", "Item 2", "Item 3", "Item 4", "Item 5"]
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        collectionView.delegate = self
        collectionView.dataSource = self
    }
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return data.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! CustomCollectionViewCell
        cell.label.text = data[indexPath.item]
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: collectionView.frame.width, height: 50)
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        let specificIndex = 2 // 特定索引处
        let indexPath = IndexPath(item: specificIndex, section: 0)
        collectionView.scrollToItem(at: indexPath, at: .centeredVertically, animated: true)
    }
}