}

func (r *Request) multipartReader(allowMixed bool) (*multipart.Reader, error) {
	v := r.Header.Get("Content-Type")
	if v == "" {
		return nil, ErrNotMultipart
	}
	if r.Body == nil {
		return nil, errors.New("missing form body")
	}
	d, params, err := mime.ParseMediaType(v)
	if err != nil || !(d == "multipart/form-data" || allowMixed && d == "multipart/mixed") {
		return nil, ErrNotMultipart
	}