docs: public ByteBuffer readData() throws Exception {
          ColumnList<C> result = keyspace
                  .prepareQuery(columnFamily)
                      .setConsistencyLevel(consistencyLevel)
                      .getKey(key)
                  .execute()
                      .getResult();
          
          boolean hasColumn = false;
          ByteBuffer data = null;
          for (Column<C> column : result) {
              if (column.getTtl() == 0) {
                  if (hasColumn) {
                      throw new IllegalStateException("Row has multiple uniquneness locks");
                  }
                  hasColumn = true;
                  data = column.getByteBufferValue();
              }
          }
          
          if (!hasColumn) {
              throw new NotFoundException(this.key.toString() + " has no uniquness lock");
          }
          return data;
      }