static hasDST(zone = Settings.defaultZone) {
    const proto = DateTime.now().setZone(zone).set({ month: 12 });

    return !zone.isUniversal && proto.offset !== proto.set({ month: 6 }).offset;
  }
Return whether the specified zone contains a DST.
@param {string|Zone} [zone='local'] - Zone to check. Defaults to the environment's local zone.
@return {boolean}