code: public void waitForCloseToComplete()
     {
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc, "waitForCloseToComplete");
  
        closeWaitersMonitor.waitOn();
  
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc, "waitForCloseToComplete");
     }
docs: Blocks until a close operation has completed.  I.e. the priority queue has been
  drained.  If the queue is already closed, this method returns immeidately.