public function getRequestHeaders($auth = true)
    {
        $headers = \getallheaders();
        if($auth) {
            $hmac = $this->getRest()->getServer()->getHmac();
            $return = array(
                $hmac->getPrefix().'timestamp' => (isset($headers[$hmac->getPrefix().'timestamp']) ? $headers[$hmac->getPrefix().'timestamp'] : ''),
                $hmac->getPrefix().'signature' => (isset($headers[$hmac->getPrefix().'signature']) ? $headers[$hmac->getPrefix().'signature'] : ''),
                $hmac->getPrefix().'key' => (isset($headers[$hmac->getPrefix().'key']) ? $headers[$hmac->getPrefix().'key'] : ''),
                $hmac->getPrefix().'version' => (isset($headers[$hmac->getPrefix().'version']) ? $headers[$hmac->getPrefix().'version'] : ''),
            );
            $headers = $return;
        }
        
        return $headers;
    }