public ScheduledChore createCleanupScheduledChore(Stoppable stoppable) {
    // By default, it will run every 6 minutes (30 / 5).
    return new ScheduledChore("nonceCleaner", stoppable, deleteNonceGracePeriod / 5) {
      @Override
      protected void chore() {
        cleanUpOldNonces();
      }
    };
  }
Creates a scheduled chore that is used to clean up old nonces.
@param stoppable Stoppable for the chore.
@return ScheduledChore; the scheduled chore is not started.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/ServerNonceManager.java