async fn watch(
target_actors: &mut TargetActors,
termination_events: Receiver<TerminationMessage>,
target_actor_output_events: Receiver<TargetActorOutputMessage>
) -> Result<()>
async fn watch(
target_actors: &mut TargetActors,
termination_events: Receiver<TerminationMessage>,
target_actor_output_events: Receiver<TargetActorOutputMessage>
) -> Result<()>