EventSubscriber.scala

override val requestStrategy = new RequestStrategy {
  override def requestDemand(remainingRequested: Int) =
    Math.max(remainingRequested, 1)
}

override def receive = {
  case OnNext(message: Message) =>
    val gameEvent =
      GameEvent(
        gameId = message.headers("gameId"),
        eventType = message.headers("type"),
        data = Json.parse(message.body.decodeString("UTF-8")))
    publisher ! gameEvent
}