以下是一个可以工作的Akka Actor源代码实现方式：

import akka.actor._

import scala.concurrent.duration._

case class PingMessage(id: Int, msg: String)
case class PongMessage(id: Int, msg: String)

class Ping(pong: ActorRef) extends Actor {
  var count = 0

  def incrementAndPrint {
    count += 1
    println(s"ping $count")
  }

  def receive = {
    case StartMessage =>
      println("start")
      incrementAndPrint
      pong ! PingMessage(count, "ping")

    case PongMessage(id, msg) =>
      incrementAndPrint
      if (count > 99) {
        sender ! StopMessage
        println("ping stopped")
        context.stop(self)
      } else {
        sender ! PingMessage(count, "ping")
      }
  }
}

class Pong extends Actor {
  def receive = {
    case PingMessage(id, msg) =>
      println(s"  pong $id")
      sender ! PongMessage(id, "pong")
    case StopMessage =>
      println("pong stopped")
      context.stop(self)
  }
}

case object StartMessage
case object StopMessage

val system = ActorSystem("PingPongSystem")

val pong = system.actorOf(Props[Pong], name = "pong")
val ping = system.actorOf(Props(new Ping(pong)), name = "ping")
ping ! StartMessage

system.awaitTermination()

通过这种方式实现的Akka Actor源代码可以确保滑动窗口的行为符合预期，而且执行的非常好。