docs: public void close(boolean immediate)
     {
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc, "close", ""+immediate);
  
        synchronized(queueMonitor)
        {
           if (immediate || (totalQueueDepth == 0))
           {
              state = CLOSED;
              closeWaitersMonitor.setActive(false);
           }
           else
              state = CLOSING;
        }
  
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc, "close");
     }