const Base64Url:  brand(
  "Base64Url",
  String,
  (value) => {
    const decoded = trySync(() => base64UrlStringToUint8Array(value));

    return decoded.ok && uint8ArrayToBase64UrlString(decoded.value) === value
      ? ok()
      : err<Base64UrlError>({ type: "Base64Url", value });
  },
  (error) =>
    The value ${safelyStringifyUnknownValue(error.value)} is not a valid Base64Url string.,
) ;