Lack of documentation: examples of plural forms usage for non trivial locales (e.g: ru, ja, zh_CN)

[romangoward]

Hi folk,
currently I am working on localization of our dart applications and I have a misunderstanding of plural forms usage: it's not clear how to convert plural gettext dataset into arb for some specific languages. Could you please show us any examples with compiled ARB for ru, ja and zh_CN locales?

Thanks.