PausableWorker.scala

import akka.actor.{Actor, Stash}
class PausableWorker extends Actor with Stash {
  def receive = processing
  
  def processing: Receive = {
    case "pause" => context.become(paused)
    case msg => // Process task    
  }
  
  def paused: Receive = {
    case "resume" => 
      unstashAll()
      context.unbecome()
    case msg => 
      stash()
  }
}