throw new IllegalStateException("Cannot forget a reliable message delivery at this level");
   public boolean remove(Delivery d) throws Throwable   {      Routable r = d.getRoutable();      if (r.isReliable())      {         throw new IllegalStateException("Cannot forget a reliable message delivery at this level");      }      if (d instanceof CompositeDelivery)      {         throw new NotYetImplementedException("Don't know to handle composite deliveries");      }      Transaction tx = tm.getTransaction();      if (tx == null)      {         return super.remove(d);      }      registerRemoveDeliverySynchronization(tx, d);      return true;   }