Killing an actor is a cooperative task

killing-actor.scala

// Stopping the loop actor:
// - Raw PoisonPill didn't work.
// - context.stop(loopActor) didn't work.
// - Thread.interrupted() is never triggered by PoisonPill, Kill nor stop.
class LoopActor extends Actor {
    var isInterrupted = false

    override def postStop(): Unit = println("Stopping...")

    override def receive: Receive = {
      case "loop" => 
        while(!isInterrupted) {
          println("Inside the while loop")
          if (Thread.interrupted()) {
            isInterrupted = true
          }
        }
    }
  }