public long refreshAgeOfLastAppliedOp() {
    return setAgeOfLastAppliedOp(lastTimestampForAge);
  }
Refreshing the age makes sure the value returned is the actual one and not the one set a
replication time
@return refreshed age
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/MetricsSink.java