protected function setCurlProxyOptions($adapter)
    {
        $adapter->setCurlOption(CURLOPT_PROXY, $this->proxyConfig['proxy_host']);
        if (!empty($this->proxyConfig['proxy_port'])) {
            $adapter
                ->setCurlOption(CURLOPT_PROXYPORT, $this->proxyConfig['proxy_port']);
        }
    }