public static final StartTime absolute(Instant absoluteStart) {
        return new StartTime(StartTimeOption.ABSOLUTE, null, absoluteStart);
    }
@Test
    public void testStartAbsolute() {
        StartTime st = StartTime.absolute(OffsetDateTime
                .of(2017, 3, 20, 11, 43, 11, 0, ZoneOffset.ofHours(-7))
                .toInstant());
        assertEquals(StartTimeOption.ABSOLUTE, st.option());
        assertNull(st.relativeTime());
        assertEquals("2017-03-20T11:43:11-07:00", st
                .absoluteTime()
                .atOffset(ZoneOffset.ofHours(-7))
                .format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));
    }