ZMQ Push/Pull needs sleep

pushpull.scala

package com.test

import akka.actor._
import akka.zeromq._

class PullTestActor(val address: String) extends Actor {
  val pullSocket = context.system.newSocket(SocketType.Pull,
    Bind(address), Listener(self))
  def receive = {
    case m: ZMQMessage ⇒
      val s = new String(m.payload(0))
      println("Got pull message: " + s)
    case x ⇒ println("Got default case: " + x)
  }
}

object TestPushPull extends App {
  val address = "tcp://0.0.0.0:4100"
  implicit val system = ActorSystem("zmqtest")

  val pushSocket = system.newSocket(SocketType.Push, Connect(address))
  val pull = system.actorOf(Props(new PullTestActor(address)), "PullTestActor")

  //Try adding/removing this line
  Thread.sleep(1000)

  while (true) {
    println("Pushing msg")
    pushSocket ! ZMQMessage(Seq(Frame("msg")))
    Thread.sleep(1000)
  }
}