public function onReflectProgress(GenericEvent $event)
    {
        if ($response = $this->storage->fetch($event)) {
            ++$this->stats[self::STATS_HITS];
            $this->hashUserData = sha1(serialize($response));
            $event['notModified'] = $response;
        } else {
            $this->hashUserData = null;
        }
    }