message: Use real execution context, as we may send exit_msgs to monitoring actors.
diff: @@ -36,7 +36,7 @@ public:
  ~actor_widget() {
  if (companion_)
  - self()->cleanup(error{}, &dummy_);
  + self()->cleanup(error{}, self()->system().dummy_execution_unit());
  }
  void init(actor_system& system) {
  