Actorul obtinerea BufferOverflowException la trimiterea Singur

Încerc să trimită câteva sute de cereri http de la akka actor cu toate acestea sunt obtinerea

akka.stream.BufferOverflowException: Exceeded configured max-open-requests value of [16]. This means that the request queue of this pool (HostConnectionPoolSetup(places.api.here.com,443,ConnectionPoolSetup(ConnectionPoolSettings(16,1,5,16,1,Duration.Inf,100 milliseconds,2 minutes,30 seconds,ClientConnectionSettings(Some(User-Agent: akka-http/10.2.0)...

această aplicație.conf

   http {
          host-connection-pool {
            max-connections = 16
            min-connections = 1
            max-open-requests = 16
          }
        }

Acest cod

override def receive: Receive = {
      case Foo(_) => 
       val res: Future[HttpResponse] = Http().singleRequest(HttpRequest(uri = "http://..."))
   // do something for the result

Am încercat să-controlul de stat e.g

override def receive: Receive = run(0)
def run(openRequests: Int) : Receive = {
  case Foo(_) if openRequests <= 16 => 
     context.become(run(openRequests + 1))
       val responseFuture: Future[HttpResponse] = Http().singleRequest(HttpRequest(uri = "http://..."))
       responseFuture.foreach(context.become(run(openRequests - 1)))
        //...

oricum am aceeași excepție de BufferOverflowException

orice sfat va fi apreciat foarte mult