private static void sortListZonedDateTime(List<ZonedDateTime> list) {

    long start = System.nanoTime();
    Collections.sort(list);
    long end = System.nanoTime();
    System.out.println("ZonedDT:   Sort:   " + NF.format(end - start) + " ns");
    result("ZonedDT-S", end - start);
  }