public long extractSequenceNumber(final ByteBuffer keyBuffer, final int offset) {
        final int len = keyBuffer.limit() - offset;
        if (len == 0) {
            return 0;
        }
        final UnsignedBytes unsignedBytes = UnsignedBytesInstances.ofLength(len);
        return unsignedBytes.get(keyBuffer, offset);
    }
Extracts the sequence number value from the keyBuffer.
Absolute, no flip required
stroom-lmdb/src/main/java/stroom/lmdb2/LmdbKeySequence.java