code: public void unsetAsynchConsumerCallback(int requestNumber, boolean stoppable)                        //SIB0115d.comms
     {
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc, "unsetAsynchConsumerCallback", "requestNumber="+requestNumber+",stoppable="+stoppable);
  
        checkNotBrowserSession();                                   // F171893
  
        if (subConsumer != null)
        {
           subConsumer.unsetAsynchConsumerCallback(requestNumber, stoppable);                             //SIB0115d.comms
        }
  
        subConsumer = null;
  
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc, "unsetAsynchConsumerCallback");
     }
docs: This method will unset the asynch consumer callback. This means that the
  client has requested that the session should be converted from asynchronous to
  synchronous and so the sub consumer must be changed
  
  @param requestNumber