AkkaRateLimiter.scala

class AkkaRateLimiter(rateLimiterActor: ActorRef) {
  def runLimited[T](f: => Future[T])(implicit ec: ExecutionContext): Future[T] = {
    val p = Promise[T]
    val msg = LazyFuture(() => f.andThen { case r => p.complete(r) }.map(_ => ()))
    rateLimiterActor ! msg
    p.future
  }
}

object AkkaRateLimiter {
  def create(maxRuns: Int, per: FiniteDuration)(
    implicit actorSystem: ActorSystem): AkkaRateLimiter = {
    
    val rateLimiterActor = actorSystem.actorOf(
      Props(new RateLimiterActor(maxRuns, per)))
    new AkkaRateLimiter(rateLimiterActor)
  }
}