public string GetLogoutRequest(string logoutRequestId, string sessionIndex, string subject, string relayState)
        {
            var signingCertificate = _certificateProvider.GetCertificate();

            var logoutRequest = _saml2MessageFactory.CreateLogoutRequest(logoutRequestId, sessionIndex, subject);

            return(_httpRedirectBinding.BuildLogoutRequestUrl(logoutRequest,
                                                              signingCertificate.ServiceProvider.PrivateKey, _identityProviderConfiguration.HashingAlgorithm,
                                                              relayState));
        }