from akka 2.0 doku:
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import akka.dispatch.PriorityGenerator
import akka.dispatch.UnboundedPriorityMailbox
import com.typesafe.config.Config
val generator = PriorityGenerator { // Create a new PriorityGenerator, lower prio means more important
case 'highpriority ⇒ 0 // 'highpriority messages should be treated first if possible
case 'lowpriority ⇒ 100 // 'lowpriority messages should be treated last if possible
case PoisonPill ⇒ 1000 // PoisonPill when no other left
case otherwise ⇒ 50 // We default to 50
}
// We create a new Priority dispatcher and seed it with the priority generator
class PrioMailbox(config: Config) extends UnboundedPriorityMailbox(generator)