intl_translation package, provide a list that contains all the locales name from ARB files that can be used to supported locales for APP.

[codelovercc]

I noticed that in the generated code file messages_all_locales.dart has some code:

Map<String, LibraryLoader> _deferredLibraries = {
  'en': messages_en.loadLibrary,
  'zh': messages_zh.loadLibrary,
};

It's a map that use the exists locale name as the key, I want use these keys as my application supported locales, so I don't need to hardcode or maintain a supported locale list by my hand. _deferredLibraries is a private global field so I can't access it.

Describe the solution you'd like
Provide a list of the existing locale when the codes have been generated, so we can use it as the application supported locale list.

Describe alternatives you've considered
Generate a global field in file messages_all_locales.dart and export it in messages_all.dart:

final List<String> existsLocales = [
    'en',
    'zh',
    'zh-CN',
    ...etc
];