message: Fix potential segfault with thread callbacks
diff: @@ -119,8 +119,8 @@ void blocking_actor::launch(execution_unit*, bool, bool hide) {
  self->on_exit();
  # endif
  self->cleanup(std::move(rsn), self->context());
  - ptr->home_system->dec_detached_threads();
  ptr->home_system->thread_terminates();
  + ptr->home_system->dec_detached_threads();
  }, strong_actor_ptr{ctrl()}).detach();
  }
  