Adds throttle example

akka-docs/src/test/scala/docs/stream/operators/sourceorflow/Throttle.scala

@@ -0,0 +1,45 @@
+package docs.stream.operators.sourceorflow
+
+import akka.NotUsed
+import akka.actor.ActorSystem
+import akka.stream.ThrottleMode
+import akka.stream.scaladsl.Sink
+import akka.stream.scaladsl.Source
+
+import scala.concurrent.duration._
+
+/**
+ * 
+ */
+object Throttle extends App {
+
+  implicit val sys = ActorSystem("25fps-stream")
+
+  val frameSource: Source[Int, NotUsed] =
+    Source.fromIterator(() => Iterator.from(0))
+
+  // #throttle
+  val framesPerSecond = 24
+
+  // val frameSource: Source[Frame,_]
+  val videoThrottling = frameSource
+    .throttle(
+      framesPerSecond,
+      1.second,
+      framesPerSecond * 30, // maximumBurst
+      ThrottleMode.shaping
+    )
+  // serialize `Frame` and send over the network.
+  // #throttle
+
+  videoThrottling
+    .to(Sink.foreach(println))
+    .run()
+}
+
+object ThrottleCommon{
+
+  // used in ThrottleJava
+  case class Frame(i: Int)
+
+}