code: public boolean put(DeliveryDelayableReference deliveryDelayableReference)
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "put", "ObjId=" + deliveryDelayableReference.getID() + " ET=" + deliveryDelayableReference.getDeliveryDelayTime());
  
          boolean reply = tree.insert(deliveryDelayableReference);
          if (reply)
          {
              size++;
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "put", "reply=" + reply);
          return reply;
      }
docs: Add an DeliveryDelayableReference to the DeliveryDelay index.
  
  @param deliveryDelayableReference an DeliveryDelayableReference.
  @return true if the object was added to the index successfully.