Macro behavior 

behavior!() { /* proc-macro */ }

Create a [Referable] definition, handling a specific set of message types. Behaviors are used to create an [ActorRef] without having to depend on the actor’s implementation. Casts are supported for any remote message handled by the actor.

hyperactor::behavior!(TestActorBehavior, TestMessage, (), MyGeneric<()>, u64,);

This macro also supports generic behaviors:

hyperactor::behavior!(TestBehavior<T>, Message<T>, u64,);