Function spawn 

pub async fn spawn<T>(
    args: <T as Actor>::Arguments,
) -> Result<(ActorRef<<T as Actor>::Msg>, JoinHandle<()>), SpawnErr>
where
    T: Actor + Default,

Perform a background-spawn of an actor. This is a utility wrapper over Actor::spawn which assumes the actor implementation implements Default.

• args - The arguments to start the actor

Returns [Ok((ActorRef, JoinHandle<()>))] upon successful actor startup, [Err(SpawnErr)] otherwise