bool delazify(JSContext *cx, HandleObject headers) {
  RootedObject backing_map(cx, detail::backing_map(headers));
  return detail::ensure_all_header_values_from_handle(cx, headers, backing_map);
}
bool delazify(JSContext *cx, HandleObject headers) {
  RootedObject backing_map(cx, detail::backing_map(headers));
  return detail::ensure_all_header_values_from_handle(cx, headers, backing_map);
}