public static TimestampRange of(Timestamp from, Timestamp to) {
    return new TimestampRange(from, to);
  }
@Test(expected = IllegalArgumentException.class)
  public void testTimestampRangeWhenFromIsGreaterThanTo() {
    TimestampRange.of(Timestamp.ofTimeMicroseconds(11L), Timestamp.ofTimeMicroseconds(10L));
  }