public static int hashCode(byte[] bytes, int offset, int length) {
        int hash = 1;
        for (int i = offset; i < offset + length; i++) {
            hash = (31 * hash) + bytes[i];
        }
        return hash;
    }
Calculate the hash code for a given range of bytes.

@param bytes  array to hash
@param offset offset to start from
@param length length to hash
stroom-bytebuffer/src/main/java/stroom/bytebuffer/hbase/Bytes.java