function shouldPolyfill() {
        return (typeof Intl === 'undefined' ||
            !('Locale' in Intl) ||
            // https://bugs.chromium.org/p/v8/issues/detail?id=10682
            new Intl.Locale('und-x-private').toString() === 'x-private');
    }
https://tc39.es/proposal-intl-locale/#sec-Intl.Locale.prototype.region