function requestViaDynamicImport(url, additionalAttributes) {
  const scriptUrl = `data:text/javascript,import("${url}");`;
  const script = createElement(
      "script",
      Object.assign({"src": scriptUrl}, additionalAttributes),
      document.body,
      false);

  return bindEvents2(window, "message", script, "error", window, "error")
    .then(event => wrapResult(event.data));
}
Creates a new script element that performs a dynamic import to `url`, and
appends the script element to {@code document.body}.
@param {string} url The src URL.
@return {Promise} The promise for success/error events.