@Override
    public int compare(final ByteBuffer buffer1, final ByteBuffer buffer2) {
        return compare(buffer1, buffer1.position(), buffer2, buffer2.position());
    }
Each instance provides methods for working with unsigned longs that are written
to len bytes. The maximum numeric value of the unsigned value will be governed
by len, e.g for len == 1, the range of values are 0-255.
stroom-lmdb/src/main/java/stroom/lmdb/serde/UnsignedBytesInstances.java