/**
  * Handle an incoming request.
  *
  * @param  \Illuminate\Http\Request  $request
  * @param  \Closure  $next
  * @return mixed
  */
 public function handle($request, Closure $next)
 {
     if ($this->session->has($this->sessionKey)) {
         $this->googleTagManager->set($this->session->get($this->sessionKey));
     }
     $response = $next($request);
     $this->session->flash($this->sessionKey, $this->googleTagManager->getFlashData());
     return $response;
 }