--- /dev/null
+<?php
+
+require __DIR__.'/common.inc';
+
+use Symfony\Component\HttpFoundation\Session\Flash\FlashBag;
+use Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage;
+
+$storage = new NativeSessionStorage();
+$storage->setSaveHandler(new TestSessionHandler());
+$flash = new FlashBag();
+$storage->registerBag($flash);
+$storage->start();
+
+$flash->add('foo', 'bar');
+
+print_r($flash->get('foo'));
+echo empty($_SESSION) ? '$_SESSION is empty' : '$_SESSION is not empty';
+echo "\n";
+
+$storage->save();
+
+echo empty($_SESSION) ? '$_SESSION is empty' : '$_SESSION is not empty';
+
+ob_start(function ($buffer) { return str_replace(session_id(), 'random_session_id', $buffer); });