@Override
    public int hashCode() {
        if (hashCode == 0) {
            hashCode = Arrays.hashCode(bytes);
        }

        return hashCode;
    }
The hashcode is cached except for the case where it is computed as 0, in which
case we compute the hashcode on every call.

@return the hashcode
jraft-core/src/main/java/com/alipay/sofa/jraft/util/Bytes.java