Akka图流无法产生输出

Question

我只是在播放akka流文档页面上提供的示例：http://doc.akka.io/docs/akka/2.4.2/scala/stream/stream-graphs.html

下面的例子没有产生输出。有人能指出这里有什么问题吗？

更新：它正在终端上工作。但在Intellij中失败

我的SBT依赖关系是：

val akkaVersion = "2.3.7"
val httpVersion = "2.0.4"
libraryDependencies ++= Seq(
  "com.typesafe.akka" %% "akka-actor" % "2.3.11",
  "com.typesafe.akka" %% "akka-stream-experimental" % httpVersion,
  "com.typesafe.akka" %% "akka-http-core-experimental" % httpVersion,
  "com.typesafe.akka" %% "akka-http-experimental" % httpVersion,
  "com.typesafe.akka" %% "akka-http-spray-json-experimental" % httpVersion
)

计划：

import akka.stream.ClosedShape


object Test extends App {

  import akka.actor.ActorSystem
  import akka.stream.ActorMaterializer
  import akka.stream.scaladsl._

  implicit val system = ActorSystem()
  implicit val materializer = ActorMaterializer()
  implicit val ec = system.dispatcher

  val source = Source(Stream.from(1))

  val graph = RunnableGraph.fromGraph(GraphDSL.create() { implicit b =>
    import GraphDSL.Implicits._

    val zip = b.add(ZipWith((left: Int, right: Int) => left))
    val bcast = b.add(Broadcast[Int](2))
    val concat = b.add(Concat[Int]())
    val start = Source.single(0)

    source ~> zip.in0
    zip.out.map { s => println(s); s } ~> bcast ~> Sink.ignore
    zip.in1 <~ concat <~ start
    concat <~ bcast
    ClosedShape
  })

  graph.run()

  Thread.sleep(1000000)
}