_onLocaleChanged(newLocale, oldLocale) {
    // Event firing immediately, does not wait for loading the translations
    this.dispatchEvent(new CustomEvent('__localeChanging'));
    if (newLocale === oldLocale) return;

    if (this._autoLoadOnLocaleChange) {
      this._loadAllMissing(newLocale, oldLocale);
      this.loadingComplete.then(() => {
        this.dispatchEvent(new CustomEvent('localeChanged', { detail: { newLocale, oldLocale } }));
      });
    } else {
      this.dispatchEvent(new CustomEvent('localeChanged', { detail: { newLocale, oldLocale } }));
    }
  }
@param {string} newLocale
@param {string} oldLocale
@returns {undefined}
@protected