resolvedLocaleOptions(opts = {}) {
    const { locale, numberingSystem, calendar } = Formatter.create(
      this.loc.clone(opts),
      opts
    ).resolvedOptions(this);
    return { locale, numberingSystem, outputCalendar: calendar };
  }
Returns the resolved Intl options for this DateTime.
This is useful in understanding the behavior of formatting methods
@param {Object} opts - the same options as toLocaleString
@return {Object}