bootSession example

ReverseProxyMiddleware::setSettingsOnRequest($request, Settings::getInstance());
      $this->boot();
      $container = $this->getContainer();
      /** @var \Symfony\Component\HttpFoundation\RequestStack $request_stack */
      $request_stack = $container->get('request_stack');
      $request_stack->push($request);
      $this->preHandle($request);

      // Handle the actual request. We need the session both for authentication       // as well as the DB update, like       // \Drupal\system\Controller\DbUpdateController::batchFinished.       $this->bootSession($request);
      $result = $this->handleRaw($request);
      $this->shutdownSession($request);

      return $result;
    }
    catch (\Exception $e) {
      return $this->handleException($e, $request, $type);
    }
  }

  /** * Generates the actual result of update.php. * * The actual logic of the update is done in the db update controller. * * @param \Symfony\Component\HttpFoundation\Request $request * The incoming request. * * @return \Symfony\Component\HttpFoundation\Response * A response object. * * @see \Drupal\system\Controller\DbUpdateController */