code: private final boolean remove(DeliveryDelayableReference deliveryDelayableReference, boolean unlocked)
      {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "remove",
                          " deliveryDelayableReference=" + deliveryDelayableReference + " unlocked=" +
                                          unlocked + " deliveryDelayIndex=" + deliveryDelayIndex.size());
  
          boolean reply = false;
          // synchronize on the lockObject
          synchronized (lockObject)
          {
              reply = deliveryDelayIndex.remove();
          }
          if (reply)
          {
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                  SibTr.debug(tc, "Removed (" + (unlocked ? "unlocked" : "gone") + ")" + " DDT=" + deliveryDelayableReference.getDeliveryDelayTime() + " objId="
                                  + deliveryDelayableReference.getID() + " DeliveryDelayIndexSize=" + deliveryDelayIndex.size());
          }
          else
          {
              // can happen if the element is already deleted
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())
                  SibTr.debug(tc, "Did not remove from index: " + " DDT=" + deliveryDelayableReference.getDeliveryDelayTime() + " objId=" + deliveryDelayableReference.getID());
          }
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "remove", "deliveryDelayIndex=" + deliveryDelayIndex.size() + " reply=" + reply);
  
          return reply;
      }
docs: Remove the DeliveryDelayable reference from the DeliveryDelay index. This will remove the
  current entry pointed-to by the iterator.
  
  @param deliveryDelayableReference our reference to the DeliveryDelayable
  @param unlocked true if the item is being removed after delivery delay time, false if being
  removed because it is no longer in store. Used for diagnostics only.
  
  @return true if the object was successfully removed from the index.