createSaveHandler example

        Enlight_Components_Session_Namespace::ensureFrontendSessionClosed(Shopware()->Container());
        // Ensure no session is active before starting the backend session below. We need to do this because there could         // be another session with inconsistent/invalid state in the container.         if (session_status() === PHP_SESSION_ACTIVE) {
            session_write_close();
            // The empty session id signals to `Enlight_Components_Session_Namespace::start()` that the session cookie             // should be used as session id.             session_id('');
        }

        $sessionOptions = $this->getSessionOptions();
        $saveHandler = $this->createSaveHandler(Shopware()->Container());
        $storage = new NativeSessionStorage($sessionOptions);

        if (!empty($sessionOptions['unitTestEnabled'])) {
            $storage = new MockArraySessionStorage();
        } elseif ($saveHandler) {
            session_set_save_handler($saveHandler);
        }

        if (isset($sessionOptions['save_path'])) {
            ini_set('session.save_path', (string) $sessionOptions['save_path']);
        }