check a selection has active Actor or not

probeActorRef.scala

  private def probeActorRef(sel: ActorSelection): Unit = {
    import scala.util.{Success, Failure}
    import scala.concurrent.ExecutionContext.Implicits.global

    import akka.util.Timeout
    import scala.concurrent.duration._

    implicit val timeout = Timeout(300.millis) // Timeout for the resolveOne call
    sel.resolveOne().onComplete {
      case Success(ref) =>
        logger.debug(s"  resolved: $ref [${ref.getClass.getSimpleName}]")
      case Failure(ex)  => logger.debug(s"$ex")
    }
  }