createRequestOptions example

  protected function registerRequest($name, $include_password = TRUE, $include_email = TRUE) {
    $user_register_url = Url::fromRoute('user.register')
      ->setRouteParameter('_format', static::$format);
    $request_body = $this->createRequestBody($name, $include_password, $include_email);
    $request_options = $this->createRequestOptions($request_body);
    $response = $this->request('POST', $user_register_url, $request_options);

    return $response;
  }

  /** * {@inheritdoc} */
  protected function setUpAuthorization($method) {
    switch ($method) {
      case 'POST':