for::setHttpHeaders

public function setHttpHeaders($httpHeaders = null)
    {
        // use global _SERVER if $httpHeaders aren't defined
        if (!is_array($httpHeaders) || !count($httpHeaders)) {
            $httpHeaders = $_SERVER;
        }

        // clear existing headers
        $this->httpHeaders = array();

        // Only save HTTP headers. In PHP land, that means only _SERVER vars that
        // start with HTTP_.
        foreach ($httpHeaders as $key => $value) {
            if (mb_substr($key, 0, 5) === 'HTTP_') {
                $this->httpHeaders[$key] = $value;
            }
        }
    }