@Override
    public long checksum() {
        byte[] bs = new byte[16];
        Bits.putLong(bs, 0, this.index);
        Bits.putLong(bs, 8, this.term);
        return CrcUtil.crc64(bs);
    }
@Test
    public void testChecksum() {
        LogId logId = new LogId();
        logId.setIndex(1);
        logId.setTerm(2);
        long c = logId.checksum();
        assertTrue(c != 0);
        assertEquals(c, logId.checksum());
    }