Create a Reactive Streams Publisher from an actor

rsFromActor.scala

  def scheduledPublisher(buffer: Int, initialDelay: FiniteDuration, interval: FiniteDuration)(
      implicit actorSystem: ActorSystem): Publisher[Unit] = {
    val actorSource = Source.actorRef[Unit](50, OverflowStrategy.fail)

    val (actorRef, publisher) = actorSource.toMat(Sink.asPublisher(fanout = false))(Keep.both).run()

    actorSystem.scheduler.schedule(initialDelay, interval, actorRef, ())
    publisher
  }