刚发现一个ios13下的BUG，同样代码ios12没问题

[nirvana72]

UICollectionViewCell高度自适应，
用的是自定义cell 中的 preferredLayoutAttributesFitting 方法来返回每个cell的经计算后的不同高度
下拉刷新时，崩溃了， IOS12下是好的，也在项目中用了好久了

最小重现代码如下：
`import UIKit
import PullToRefreshKit

class TestViewController: UIViewController, UICollectionViewDataSource {
@IBOutlet weak var collectionView: UICollectionView!
@IBOutlet weak var layout: UICollectionViewFlowLayout!

override func viewDidLoad() {
    super.viewDidLoad()
    layout.estimatedItemSize = CGSize(width: UIScreen.main.bounds.width, height: 0)
    collectionView.dataSource = self
    collectionView.register(MyCollectionViewCell.self, forCellWithReuseIdentifier: "cell")
    
    let refreshHeader = ElasticRefreshHeader()
    self.collectionView.configRefreshHeader(with: refreshHeader, container: self) { [weak self] in
        print("refreshHeader")
        self?.collectionView.switchRefreshHeader(to: .normal(.success, 0.5))
    }
}

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return 100
}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! MyCollectionViewCell
    cell.backgroundColor = UIColor.red
    return cell
}

}

class MyCollectionViewCell: UICollectionViewCell {
override func preferredLayoutAttributesFitting(_ layoutAttributes: UICollectionViewLayoutAttributes) -> UICollectionViewLayoutAttributes {
var newFrame = layoutAttributes.frame
newFrame.size.height = 100 // 这里根据内容计算出每个cell的不同高度
layoutAttributes.frame = newFrame
return layoutAttributes
}
}`

[musbah98]

Any body Solve it ??