Juggle - Concurrent Task Processing With a Single Actor - https://medium.com/kifi-engineering/juggle-concurrent-task-processing-with-a-single-actor-ed9f33c713cf

Juggle - BatchProcessingActor.scala

trait BatchProcessingActor[T] extends ConcurrentTaskProcessingActor[Seq[T]] { _: Actor =>
  final protected val minConcurrentTasks: Int = 1
  final protected val maxConcurrentTasks: Int = 1
 
  final protected def pullTasks(limit: Int): Future[Seq[Seq[T]]] = {
    if (limit == 1) nextBatch.map(Seq(_).filter(_.nonEmpty))(immediately) else Future.successful(Seq.empty)
  }
  final protected def processTasks(tasks: Seq[Seq[T]]): Map[Seq[T], Future[Unit]] = {
    tasks.map { batch => batch -> processBatch(batch) }.toMap
  }
 
  protected def nextBatch: Future[Seq[T]]
  protected def processBatch(batch: Seq[T]): Future[Unit]
}