$response = Drupal::httpClient()->post(
            'http://api.swappr.localhost/user/login?_format=hal_json',
            ['name' => 'logintest2@gmail.com', 'pass' => 'password']
        );

cURL error 28: Operation timed out after 30001 milliseconds with 0 bytes received (see http://curl.haxx.se/libcurl/c/libcurl-errors.html)