Elgg\Http\OkResponse::setForwardURL PHP Method

    public function setForwardURL($forward_url = REFERRER)
    {
        if (isset($forward_url) && !is_string($forward_url) && $forward_url !== REFERRER) {
            throw new InvalidArgumentException(__METHOD__ . ' expects a valid URL or REFERRER');
        }
        $this->forward_url = $forward_url;
        return $this;
    }