StreamHandler example

if (\function_exists('curl_multi_exec') && \function_exists('curl_exec')) {
                $handler = Proxy::wrapSync(new CurlMultiHandler(), new CurlHandler());
            } elseif (\function_exists('curl_exec')) {
                $handler = new CurlHandler();
            } elseif (\function_exists('curl_multi_exec')) {
                $handler = new CurlMultiHandler();
            }
        }

        if (\ini_get('allow_url_fopen')) {
            $handler = $handler
                ? Proxy::wrapStreaming($handler, new StreamHandler())
                : new StreamHandler();
        } elseif (!$handler) {
            throw new \RuntimeException('GuzzleHttp requires cURL, the allow_url_fopen ini setting, or a custom HTTP handler.');
        }

        return $handler;
    }

    /** * Get the default User-Agent string to use with Guzzle. */