public void setScanTime(long scanTimeNano, long scanTimeMillis) {
    this.scanTimeNanos = scanTimeNano;
    this.scanTimeMillis = scanTimeMillis;
  }
the tiemstamp when SamzSQL wuery starts processing the event
set by the SamzaSQL Scan oeprator, used by QueryTranslator to calculate
the Queuing Latency
samza-sql/src/main/java/org/apache/samza/sql/data/SamzaSqlRelMsgMetadata.java