@Override
    protected void map(NullWritable key, PeInputSplit value, final Context context)
      throws IOException, InterruptedException {
      Status status = context::setStatus;

      // Evaluation task
      pe.tableName = value.getTableName();
      long elapsedTime =
        this.pe.runOneClient(this.cmd, value.getStartRow(), value.getRows(), value.getTotalRows(),
          value.isFlushCommits(), value.isWriteToWAL(), value.isUseTags(), value.getNoOfTags(),
          ConnectionFactory.createConnection(context.getConfiguration()), status);
      // Collect how much time the thing took. Report as map output and
      // to the ELAPSED_TIME counter.
      context.getCounter(Counter.ELAPSED_TIME).increment(elapsedTime);
      context.getCounter(Counter.ROWS).increment(value.rows);
      context.write(new LongWritable(value.startRow), new LongWritable(elapsedTime));
      context.progress();
    }
configuration parameter name that contains the PE impl
hbase-rest/src/test/java/org/apache/hadoop/hbase/rest/PerformanceEvaluation.java