message: Fix debug name of scheduler threads
diff: @@ -54,7 +54,7 @@ public:
  auto this_worker = this;
  this_thread_ = std::thread{[this_worker] {
  CAF_SET_LOGGER_SYS(&this_worker->system());
  - detail::set_thread_name("caf.multiplexer");
  + detail::set_thread_name("caf.worker");
  this_worker->system().thread_started();
  this_worker->run();
  this_worker->system().thread_terminates();
  