An async initialization mix-in for Akka Actors

AsyncInitializer.scala

import akka.actor.{ActorRef, Actor, Stash}
import akka.pattern.pipe
import scala.concurrent.Future

trait AsyncInitializer[DEPENDENCIES] extends Stash {
  
  import context._

  case class Initialized(dependencies: DEPENDENCIES)

  def running(dependencies: DEPENDENCIES): Receive
  
  def initialize(): Future[DEPENDENCIES]

  override def preStart() = initialize().map(Initialized) pipeTo self

  def receive = uninitialized

  def uninitialized: Receive = {
    case Initialized(dependencies) =>
      unstashAll()
      become(running(dependencies))
    case msg => stash()
  }
}