@Override
 public void complete(FlowProcess process, AggregatorCall<Context> call) {
   wrapper.setDelegate(call);
   super.complete(process, wrapper);
   int output = wrapper.getOutputCollector().getCount();
   if (output > 0) {
     process.increment(
         OperationStatsUtils.COUNTER_CATEGORY, prefix + TOTAL_OUTPUT_RECORDS_COUNTER_NAME, output);
   }
 }
 @Override
 public void aggregate(FlowProcess process, AggregatorCall<Context> call) {
   super.aggregate(process, wrapper);
   process.increment(OperationStatsUtils.COUNTER_CATEGORY, prefix + INPUT_RECORDS_COUNTER_NAME, 1);
 }
 @Override
 public void start(FlowProcess process, AggregatorCall<Context> call) {
   super.start(process, call);
 }