rsapi/auth.go
func (s *cookieSigner) CanAuthenticate(host string) error {
	_, instance := s.builder.(*instanceLoginRequestBuilder)
	return testAuth(s, s.client, host, instance)
}
func (s *cookieSigner) CanAuthenticate(host string) error {
	_, instance := s.builder.(*instanceLoginRequestBuilder)
	return testAuth(s, s.client, host, instance)
}
// CanAuthenticate makes a test request to CM 1.5 and returns true if it is successful.