如何使用MailKit/MimeKit将附件从一封电子邮件移动到另一封电子邮件？

using MailKit.Net.Imap;
using MailKit.Net.Smtp;
using MailKit.Security;
using MimeKit;

public void MoveAttachmentFromOneEmailToAnother()
{
    // 连接到源邮件服务器
    using (var client = new ImapClient())
    {
        client.Connect("imap.example.com", 993, SecureSocketOptions.SslOnConnect);
        client.Authenticate("username", "password");

        // 获取源邮件
        var sourceMessage = client.Inbox.GetMessage(0);

        // 解析源邮件内容
        var sourceMimeMessage = MimeMessage.Load(sourceMessage);

        // 创建新邮件
        var newMessage = new MimeMessage();
        newMessage.Subject = "New Email with Attachment";

        // 将源邮件中的附件添加到新邮件中
        foreach (var attachment in sourceMimeMessage.Attachments)
        {
            newMessage.Attachments.Add(attachment);
        }

        // 连接到目标邮件服务器
        using (var smtpClient = new SmtpClient())
        {
            smtpClient.Connect("smtp.example.com", 587, SecureSocketOptions.StartTls);
            smtpClient.Authenticate("username", "password");

            // 发送新邮件到目标邮箱
            smtpClient.Send(newMessage);

            smtpClient.Disconnect(true);
        }

        client.Disconnect(true);
    }
}