load method Null safety
- Locale locale
Implementation
static Future<Strings> load(Locale locale) {
  final name = (locale.countryCode?.isEmpty ?? false)
      ? locale.languageCode
      : locale.toString();
  final localeName = Intl.canonicalizedLocale(name);
  return initializeMessages(localeName).then((_) {
    Intl.defaultLocale = localeName;
    final instance = Strings();
    Strings._current = instance;
    return instance;
  });
}