@Override
    public Void call() throws Exception {
      log.debug("Starting VerifyLastInsertCommand");
      String key = "test";
      sliceQuery.setColumnFamily(commandArgs.workingColumnFamily);

      log.info("StartKey: {} for thread {}", key, Thread.currentThread().getId());
      String colValue;

      for (int col = 0; col < commandArgs.columnCount; col++) {
        colValue = String.format(COLUMN_VAL_FORMAT, col);
        mutator.addInsertion(key, 
                             commandArgs.workingColumnFamily, 
                             HFactory.createStringColumn(String.format(COLUMN_NAME_FORMAT, col),
                                 colValue));
        executeMutator(col);

        // Let's verify
        sliceQuery.setKey(key);
        sliceQuery.setRange(null, null, true, 1);
        QueryResult<ColumnSlice<String,String>> result = sliceQuery.execute();
        String actualValue = result.get().getColumns().get(0).getValue();

        if (!actualValue.equals(colValue)) {
          log.error("Column values don't match. Expected: " + colValue + " - Actual: " + actualValue);
          break;
        }
      }

      commandRunner.doneSignal.countDown();
      log.debug("VerifyLastInsertCommand complete");
      return null;
    }