add examples for scan operator #25468

akka-docs/src/test/scala/docs/stream/operators/SourceOrFlow.scala

@@ -52,4 +52,23 @@ object SourceOrFlow {
     //#conflateWithSeed
   }
 
+  def scanExample(): Unit = {
+    import akka.actor.ActorSystem
+    import akka.stream.ActorMaterializer
+
+    implicit val system: ActorSystem = ActorSystem()
+    implicit val materializer: ActorMaterializer = ActorMaterializer()
+
+    //#scan
+    val source = Source(1 to 5)
+    source.scan(0)((acc, x) ⇒ acc + x).runForeach(println)
+    // 0  (= 0)
+    // 1  (= 0 + 1)
+    // 3  (= 0 + 1 + 2)
+    // 6  (= 0 + 1 + 2 + 3)
+    // 10 (= 0 + 1 + 2 + 3 + 4)
+    // 15 (= 0 + 1 + 2 + 3 + 4 + 5)
+    //#scan
+  }
+
 }