func (a *rl10Authenticator) Sign(r *http.Request) error {
	r.Header.Set("X-RLL-Secret", a.secret)
	return nil
}
func (a *rl10Authenticator) Sign(r *http.Request) error {
	r.Header.Set("X-RLL-Secret", a.secret)
	return nil
}
// RL10 authenticator uses special header