如何在UIPageViewController上添加按钮？

import UIKit

class CustomViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建按钮
        let button = UIButton(type: .system)
        button.frame = CGRect(x: 100, y: 100, width: 200, height: 50)
        button.setTitle("点击按钮", for: .normal)
        button.addTarget(self, action: #selector(buttonClicked), for: .touchUpInside)
        
        // 添加按钮到视图
        view.addSubview(button)
    }
    
    @objc func buttonClicked() {
        // 按钮点击事件逻辑
        print("按钮被点击了")
    }
}

class PageViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置dataSource和delegate
        dataSource = self
        delegate = self
        
        // 创建自定义的UIViewController
        let customViewController = CustomViewController()
        
        // 设置UIPageViewController的子视图控制器数组
        setViewControllers([customViewController], direction: .forward, animated: true, completion: nil)
    }
    
    // 返回正确的子视图控制器数组
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        return nil
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        return nil
    }
}