public static byte[] addPrefixFlag(final int ordinal, final byte[] r) {
        byte[] prefix = Bytes.toBytes((short) ordinal);
        if (prefix.length != Bytes.SIZEOF_SHORT) {
          throw new RuntimeException("Unexpected size: " + prefix.length);
        }
        byte[] result = new byte[prefix.length + r.length];
        System.arraycopy(prefix, 0, result, 0, prefix.length);
        System.arraycopy(r, 0, result, prefix.length, r.length);
        return result;
      }
Returns new byte array that has <code>ordinal</code> as prefix on front taking up
Bytes.SIZEOF_SHORT bytes followed by <code>r</code>
hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestBigLinkedList.java