/**
  * @return \Symfony\Component\HttpFoundation\RedirectResponse
  */
 public function initiateSamlRequest()
 {
     $authnRequest = AuthnRequestFactory::createNewRequest($this->serviceProvider, $this->identityProvider);
     $this->stateHandler->setRequestId($authnRequest->getRequestId());
     return $this->redirectBinding->createRedirectResponseFor($authnRequest);
 }