如何知道数据在collectionView中显示在3个水平行中？

class ViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {
    var collectionView: UICollectionView!
    let yourDataArray = [/* 你的数据数组 */]

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let layout = UICollectionViewFlowLayout()
        layout.sectionInset = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
        layout.minimumInteritemSpacing = 10
        layout.minimumLineSpacing = 10
        
        let availableWidth = collectionView.bounds.width - layout.sectionInset.left - layout.sectionInset.right
        let cellWidth = (availableWidth - (layout.minimumInteritemSpacing * 2)) / 3
        layout.itemSize = CGSize(width: cellWidth, height: cellWidth)
        
        collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: layout)
        collectionView.dataSource = self
        collectionView.delegate = self
        collectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "CellIdentifier")
        view.addSubview(collectionView)
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return yourDataArray.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CellIdentifier", for: indexPath)
        // 配置cell的内容
        return cell
    }
}