load method
MUST be synchronous.
A delegate that returns a real Future makes Localizations render an
empty box and call deferFirstFrame() — a blank app until it resolves,
which is precisely the failure this SDK exists to prevent.
Implementation
@override
Future<LL> load(Locale locale) {
final String code = languageTagOf(locale);
return SynchronousFuture<LL>(LL._(client, locale, code, direction));
}