TypedAndUnionTypes.scala

  import akka.typed.Behavior
  import akka.typed.scaladsl.Actor._

  sealed trait LifecycleCommand
  object Stop extends LifecycleCommand

  val lifecycleBehavior: Behavior[LifecycleCommand] =
    immutable[LifecycleCommand]((ctx, msg) =>
      msg match {
        case Stop =>
          stopped
      }
    )

  sealed trait CounterCommand
  object Increase extends CounterCommand

  val counterBehavior: Behavior[CounterCommand] =
    deferred[CounterCommand] { (ctx) =>
      var counter = 0

      immutable((ctx, msg) =>
        msg match {
          case Increase =>
            counter += 1
            println("Counter " + counter)
            same
        }
      )
    }



  // Doesn't exist but the idea is something like
  val composed: Behavior[CounterCommand | LifecycleCommand] =
    lifecycleBehavior.orElse(counterBehavior)