docs: public void add(final ItemReference ref, final Transaction transaction)
                      throws ProtocolException, OutOfCacheSpace, StreamIsFull, TransactionException, PersistenceException, SevereMessageStoreException
      {
  
          // default lock id
          long lockId = NO_LOCK_ID;
  
          // delivery delay is set, hence DELIVERY_DELAY_LOCK_ID will be used to lock the Item
          if (ref.getDeliveryDelay() > 0)
              lockId = DELIVERY_DELAY_LOCK_ID;
  
          add(ref, lockId, transaction);
  
      }