PdfKit swift中带pdf的mailComposeViewController

import UIKit
import MessageUI
import PDFKit

class ViewController: UIViewController, MFMailComposeViewControllerDelegate {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 创建PDF文件
        let pdfView = PDFView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
        let pdfDocument = PDFDocument(url: URL(fileURLWithPath: "path_to_pdf_file"))
        pdfView.document = pdfDocument
        
        // 创建邮件视图控制器
        let mailComposeViewController = MFMailComposeViewController()
        mailComposeViewController.mailComposeDelegate = self
        mailComposeViewController.setSubject("PDF Attachment")
        mailComposeViewController.addAttachmentData(pdfDocument!.dataRepresentation(), mimeType: "application/pdf", fileName: "example.pdf")
        
        // 显示邮件视图控制器
        self.present(mailComposeViewController, animated: true, completion: nil)
    }
    
    // 邮件发送完成后的回调方法
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        controller.dismiss(animated: true, completion: nil)
    }
}