if (log.isTraceEnabled()) { log.trace("Persisted message " + r); }
   public MessageReference reference(Routable r) throws Throwable   {      if (r.isReference() || !r.isReliable())      {         return super.reference(r);      }      // is reliable      if (log.isTraceEnabled()) { log.trace("Persisting message " + r); }      pm.store((Message)r);      return new SoftMessageReference((Message)r, this);   }