将RPPreviewController中的视频保存到特定位置，而不是保存到相机胶卷中？

import ReplayKit

class ViewController: UIViewController, RPPreviewViewControllerDelegate {
    
    // 保存视频的目标URL
    let targetURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("savedVideo.mp4")
    
    // 录制完成后的回调方法
    func previewController(_ previewController: RPPreviewViewController, didFinishWithActivityTypes activityTypes: Set<String>) {
        // 获取用户录制的视频URL
        guard let videoURL = previewController.previewController?.videoURL else {
            return
        }
        
        do {
            // 将视频从默认位置移动到目标URL
            try FileManager.default.moveItem(at: videoURL, to: targetURL)
            print("视频保存成功：\(targetURL)")
        } catch {
            print("视频保存失败：\(error)")
        }
        
        // 关闭预览界面
        previewController.dismiss(animated: true, completion: nil)
    }
    
    // 用户点击保存按钮时调用
    @IBAction func saveButtonTapped(_ sender: UIButton) {
        let previewController = RPPreviewViewController()
        previewController.previewControllerDelegate = self
        present(previewController, animated: true, completion: nil)
    }
}