public void flush() {
        ByteBuffer bf = localBuffer.get();
        bf.position(0);
        bf.limit(wheelLength);
        mappedByteBuffer.position(0);
        mappedByteBuffer.limit(wheelLength);
        for (int i = 0; i < wheelLength; i++) {
            if (bf.get(i) != mappedByteBuffer.get(i)) {
                mappedByteBuffer.put(i, bf.get(i));
            }
        }
        this.mappedByteBuffer.force();
    }
@Test(expected = RuntimeException.class)
    public void testRecoveryFixedTTL() throws Exception {
        timerWheel.flush();
        TimerWheel tmpWheel = new TimerWheel(baseDir, slotsTotal + 1, precisionMs);
    }