private function prepareHandle(Notification $notification)
    {
        $request = new Request($notification, $this->isProductionEnv);
        $ch = curl_init();

        $this->authProvider->authenticateClient($request);

        curl_setopt_array($ch, $request->getOptions());
        curl_setopt($ch, CURLOPT_HTTPHEADER, $request->getDecoratedHeaders());

        // store device token to identify response
        curl_setopt($ch, CURLOPT_PRIVATE, $notification->getDeviceToken());

        return $ch;
    }