This partial function is meant to be combined with some actors' `receive` method, [whose type is](http://doc.akka.io/api/akka/2.2.0/#akka.actor.Actor$@Receive=PartialFunction[Any,Unit]) `PartialFunction[Any, Unit]`, using `andThen`:
`PartialFunction[Any, Any] andThen PartialFunction[Any, Unit]: PartialFunction[Any, Unit]`