ratelimit.scala

class ApiService[T] {
  // other code ...
  
  def request(f: () => Future[T], maxQueueTime: Duration = Duration.Inf)
             (d: LimitDetector = limitDetection)
             : Future[T] = this.synchronized {
    val p = Promise[T]()
    val startDeadline =
      if (maxQueueTime.isFinite)
        Some(LocalDateTime.now().plusSeconds(maxQueueTime.toSeconds))
      else
        None
    requestQueue.offerLast(RequestQueueItem(f, p, d, startDeadline))
    tryRequest()
    p.future
  }
  
}