broadcast to two sinks one being delayed

GraphDSL.scala

val g = RunnableGraph.fromGraph(GraphDSL.create() {
      implicit builder =>

        import GraphDSL.Implicits._

        val so = builder.add(Source.fromIterator(() => List(1, 2, 3).iterator)).out
        val p1 = builder.add(Flow[Int].scan(0)((acc, next) => acc + next))
        val p2 = builder.add(Flow[Int].delay(1.second))
        val b = builder.add(Broadcast[Int](2))
        val sa = builder.add(Sink.foreach[Int](item => {
          println(s"-=> Sink A: $item")
        })).in
        val sb = builder.add(Sink.foreach[Int](item => {
          println(s"-=> Sink B: $item")
        })).in

        so ~> p1 ~> b
              sa <~ b
        sb <~ p2 <~ b
        ClosedShape
    })
    g.run()