callback_overflow.rb

package m

import akka.stream.scaladsl._
import akka.stream._
import akka.actor._

object Main extends App {
  implicit val system = ActorSystem("hi")
  implicit val materializer = ActorMaterializer()
  implicit val ec = system.dispatcher

  val (input, completed) = Source.actorRef[Int](0, OverflowStrategy.dropNew).
    conflate { (prior, overflown) =>
      println(s"dropping overflown ${overflown}")
      prior
    }.
    buffer(10, OverflowStrategy.backpressure).
    async.
    toMat(Sink.foreach { n =>
      println(n)
      Thread.sleep(100)
    })(Keep.both).
    run

  (1 to 50).foreach { n =>
    input ! n
    println(s"sent ${n}")
    Thread.sleep(10)
  }
}