public function write(SessionBagInterface $sessionBag)
    {
        if ($this->hasRequiredParams()) {

            // Writes hashes, not values themselves
            $sessionBag->set(self::PARAM_REMOTE_ADDR, $this->hash($this->getRemoteAddr()));
            $sessionBag->set(self::PARAM_USER_AGENT, $this->hash($this->getUserAgent()));
        }
    }