How to refactor this code by using akka streams.

The idea is to keep the channel opened to use it later. In playframework 2.5.x the documentation says that you have to use akka streams but does not say anything how to achieve this example. Somebody can help me?

import play.api.mvc._
import play.api.libs.iteratee._
import play.api.libs.concurrent.Execution.Implicits.defaultContext

def socket =  WebSocket.using[String] { request =>

  // Concurrent.broadcast returns (Enumerator, Concurrent.Channel)
  val (out, channel) = Concurrent.broadcast[String]

  // log the message to stdout and send response back to client
  val in = Iteratee.foreach[String] {
    msg => println(msg)
      // the Enumerator returned by Concurrent.broadcast subscribes to the channel and will
      // receive the pushed messages
      channel push("I received your message: " + msg)
  }
  (in,out)
}