d.getReference().setRedelivered(true);  d.getReference().getMessage().setRedelivered(true);
   public boolean cancel(Delivery d) throws Throwable   {      if (log.isTraceEnabled()) { log.trace("cancel " + d); }            d.getReference().setRedelivered(true);            d.getReference().getMessage().setRedelivered(true);            state.cancel(d);            if (log.isTraceEnabled()) { log.trace(this + " marked message " + d.getReference() + " as undelivered"); }            return true;   }