code: public static ByteBuffer getIndexColumnFamily(byte[] columnFamily, byte[] columnQualifier)
      {
          return wrap(ArrayUtils.addAll(ArrayUtils.add(columnFamily, UNDERSCORE), columnQualifier));
      }
docs: Gets the column family of the index table based on the given column family and qualifier.
  
  @param columnFamily Presto column family
  @param columnQualifier Presto column qualifier
  @return ByteBuffer of the given index column family