public static String getStringInMillis(final Duration duration) {
        return duration.toMillis() + TimeUnit.MILLISECONDS.labels.get(0);
    }
@Test
    void testGetStringInMillis() {
        assertThat(TimeUtils.getStringInMillis(Duration.ofMillis(4567L))).isEqualTo("4567ms");
        assertThat(TimeUtils.getStringInMillis(Duration.ofSeconds(4567L))).isEqualTo("4567000ms");
        assertThat(TimeUtils.getStringInMillis(Duration.of(4567L, ChronoUnit.MICROS)))
                .isEqualTo("4ms");
    }