func (r *Request) SetMeta(v interface{}) error {
	b, err := json.Marshal(v)
	if err != nil {
		return err
	}
	r.Meta = (*json.RawMessage)(&b)
	return nil
}
func (r *Request) SetMeta(v interface{}) error {
	b, err := json.Marshal(v)
	if err != nil {
		return err
	}
	r.Meta = (*json.RawMessage)(&b)
	return nil
}
// SetMeta sets r.Meta to the JSON representation of v. If JSON
// marshaling fails, it returns an error.