BroadcastBehavior.scala

def broadcastBehavior(
  connector: QueueConnector[Future]): Behavior[BroadcastActorMessage] = 
  Behaviors.setup { ctx =>
    val connectBehavior = Behaviors
      .supervise[Nothing](connectToQueueBehavior(connector, ctx.self))
      .onFailure[RuntimeException](SupervisorStrategy.restart)
    ctx.spawn[Nothing](connectBehavior, "connect-queue")

    def handleMessage(
      consumers: Set[ActorRef[String]]): Behavior[BroadcastActorMessage] = // ...

    handleMessage(Set())
  }