if(!send_queue_handler.isRunning()) send_queue_handler.start();
if(!sender.isRunning()) sender.start();
        void send(Message msg) {            try {                send_queue.put(msg);                if(!send_queue_handler.isRunning())                    send_queue_handler.start();            }            catch(InterruptedException e) {                log.error("failed adding message to send_queue", e);            }        }