private void updateMetrics(long arrivalTime, long outputTime, boolean isNewInputMessage) {
      if (isNewInputMessage) {
        inputEvents.inc();
      }
      outputEvents.inc();
      processingTime.update(outputTime - arrivalTime);
    }
Updates the Diagnostics Metrics (processing time and number of events)
@param arrivalTime input message arrival time (= beging of processing in this operator)
@param outputTime output message output time (=end of processing in this operator)
@param isNewInputMessage whether the input Message is from new input message or not
samza-sql/src/main/java/org/apache/samza/sql/translator/ProjectTranslator.java