如何正确添加带有邮件的附件，特别是IOS中的RTF？

import MessageUI

func sendEmailWithAttachment() {
    if MFMailComposeViewController.canSendMail() {
        let mailComposeVC = MFMailComposeViewController()
        mailComposeVC.mailComposeDelegate = self
        mailComposeVC.setSubject("邮件主题")
        mailComposeVC.setMessageBody("邮件正文", isHTML: false)
        
        // 添加附件
        if let attachmentData = NSData(contentsOfFile: "附件文件路径") {
            mailComposeVC.addAttachmentData(attachmentData as Data, mimeType: "application/rtf", fileName: "附件文件名.rtf")
        }
        
        // 弹出邮件视图控制器
        self.present(mailComposeVC, animated: true, completion: nil)
    } else {
        // 无法发送邮件，处理错误情况
    }
}

extension ViewController: MFMailComposeViewControllerDelegate {
    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        switch result {
        case .cancelled:
            print("邮件发送取消")
        case .saved:
            print("邮件保存成功")
        case .sent:
            print("邮件发送成功")
        case .failed:
            print("邮件发送失败")
        default:
            break
        }
        
        // 关闭邮件视图控制器
        controller.dismiss(animated: true, completion: nil)
    }
}