code: public void afterRead(D record, long startTime) {
      Instrumented.updateTimer(this.extractorTimer, System.nanoTime() - startTime, TimeUnit.NANOSECONDS);
      if (record != null) {
        Instrumented.markMeter(this.readRecordsMeter);
      }
    }
docs: Called after each record is read.
  @param record record read.
  @param startTime reading start time.