如何确保我的scrollView滚动超过KeyboardSpacer的高度？

import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var scrollView: UIScrollView!
    @IBOutlet weak var contentView: UIView!
    @IBOutlet weak var scrollViewBottomConstraint: NSLayoutConstraint!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 监听键盘弹出通知
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(_:)), name: UIResponder.keyboardWillShowNotification, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(_:)), name: UIResponder.keyboardWillHideNotification, object: nil)
    }
    
    deinit {
        // 移除键盘通知的监听
        NotificationCenter.default.removeObserver(self)
    }
    
    @objc func keyboardWillShow(_ notification: Notification) {
        // 获取键盘的高度和动画持续时间
        guard let userInfo = notification.userInfo,
              let keyboardFrame = userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect,
              let animationDuration = userInfo[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double else {
            return
        }
        
        // 调整scrollView的内容区域的底部约束，使其滚动超过KeyboardSpacer的高度
        let keyboardHeight = keyboardFrame.height
        scrollViewBottomConstraint.constant = keyboardHeight - view.safeAreaInsets.bottom
        
        // 使用动画效果更新scrollView的布局
        UIView.animate(withDuration: animationDuration) {
            self.view.layoutIfNeeded()
        }
    }
    
    @objc func keyboardWillHide(_ notification: Notification) {
        // 恢复scrollView的内容区域的底部约束为0
        scrollViewBottomConstraint.constant = 0
        
        // 使用动画效果更新scrollView的布局
        UIView.animate(withDuration: 0.3) {
            self.view.layoutIfNeeded()
        }
    }
}