To support multithread safety, the rwsf::TransportImp base class invoke() method creates a multithread guard and then calls doInvoke() in derived classes. This design provides thread safety during asynchronous processing and allows your application to share transports safely. If you know you will not be using asynchronous processing with your transport and you want to avoid using the mutex guard, you can reimplement invoke() in your derived class to not use the mutex guard.