static int maskChecksum(long checksum) {
        return (int) ((checksum >> 15 | checksum << 17) + 0xa282ead8);
    }
@Test
    public void testMaskChecksum() {
        ByteBuf input = Unpooled.wrappedBuffer(new byte[] {
                0x00, 0x00, 0x00, 0x0f, 0x00, 0x00, 0x00, 0x00,
                0x5f, 0x68, 0x65, 0x61, 0x72, 0x74, 0x62, 0x65,
                0x61, 0x74, 0x5f,
        });
        assertEquals(0x44a4301f, calculateChecksum(input));
        input.release();
    }