code: public static long getId(final byte[] rowkey) {
          return (rowkey[0] & 0xFFL) << 40 | (rowkey[1] & 0xFFL) << 32 | (rowkey[2] & 0xFFL) << 24
                  | (rowkey[3] & 0xFFL) << 16 | (rowkey[4] & 0xFFL) << 8 | (rowkey[5] & 0xFFL) << 0;
      }
docs: Convert the row key to a long id.
  
  @param rowkey 6 byte row key.
  @return long representation of the row key.