code: public void incrCounter(Enum<?> key, long incr) {
      PigStatusReporter reporter = PigStatusReporter.getInstance();
      if (reporter != null && reporter.getCounter(key) != null) {
        HadoopCompat.incrementCounter(reporter.getCounter(key), incr);
        if (counterEnumMap_.size() > 0) {
          for (Map.Entry<Enum<?>, Long> entry : counterEnumMap_.entrySet()) {
            HadoopCompat.incrementCounter(
                reporter.getCounter(entry.getKey()), entry.getValue());
          }
          counterEnumMap_.clear();
        }
      } else { // buffer the increments
        Long currentValue = counterEnumMap_.get(key);
        counterEnumMap_.put(key, (currentValue == null ? 0 : currentValue) + incr);
      }
    }
docs: Mocks the Reporter.incrCounter, but adds buffering.
  See org.apache.hadoop.mapred.Reporter's incrCounter.