webApi MailKit 发送邮件附件，中文附件名在QQ邮箱乱码

Question

public static IList<MimePart> GetMimePartList()
{
IList<MimePart> mimePartList = new List<MimePart>();var current = HttpContext.Current;if (current != null)
{
HttpRequest request = current.Request;
HttpFileCollection files = request.Files;int filesCount = files.Count;for (int i = 0; i < filesCount; i++)
{
HttpPostedFile item = files[i];
MimePart attachment = new MimePart(item.ContentType)
{
ContentObject = new ContentObject(item.InputStream, ContentEncoding.Default),
ContentDisposition = new ContentDisposition(ContentDisposition.Attachment),
ContentTransferEncoding = ContentEncoding.Base64,
FileName = item.FileName
};

mimePartList.Add(attachment);
}
}return mimePartList;
}