Jaybizzle\CrawlerDetect\CrawlerDetect::setUserAgent PHP Method

    public function setUserAgent($userAgent = null)
    {
        if (false === empty($userAgent)) {
            $this->userAgent = $userAgent;
        } else {
            $this->userAgent = null;
            foreach ($this->getUaHttpHeaders() as $altHeader) {
                if (false === empty($this->httpHeaders[$altHeader])) {
                    // @todo: should use getHttpHeader(), but it would be slow.
                    $this->userAgent .= $this->httpHeaders[$altHeader] . ' ';
                }
            }
            $this->userAgent = !empty($this->userAgent) ? trim($this->userAgent) : null;
        }
    }