public static String getPrettyStringMs(long timestampMs) {
        StringBuilder builder = new StringBuilder();
        printTimeMs(timestampMs, builder);
        return builder.toString();
    }
@Test
    public void testGetPrettyStringMs() {
        // 6hour1min
        Assert.assertEquals(DebugUtil.getPrettyStringMs(21660222), "6h1m");

        // 1min222ms
        Assert.assertEquals(DebugUtil.getPrettyStringMs(60222), "1m");

        // 2s222ms
        Assert.assertEquals(DebugUtil.getPrettyStringMs(2222), "2s222ms");

        // 22ms
        Assert.assertEquals(DebugUtil.getPrettyStringMs(22), "22ms");
    }