public static String format(Date date) {
    return format(date, false, TIMEZONE_UTC);
  }
@Test
  @SuppressWarnings("JavaUtilDate")
  public void testDateFormatWithMilliseconds() {
    long time = 1530209176870L;
    Date date = new Date(time);
    String dateStr = ISO8601Utils.format(date, true);
    String expectedDate = "2018-06-28T18:06:16.870Z";
    assertThat(dateStr).isEqualTo(expectedDate);
  }