@Override
    public byte[] encode() {
        byte[] bs = new byte[2];
        short val = (short) (this.isOldStorageExist ? 1 : 0);
        Bits.putShort(bs, 0, val);
        return bs;
    }
This checkpoint is used for saving whether the oldStorage in HybridStorage is shutdown
jraft-extension/java-log-storage-impl/src/main/java/com/alipay/sofa/jraft/storage/file/assit/HybridStorageStatusCheckpoint.java