These are messages that are sent to an actor, but are not handled in the receive function. This only applies to the Scala actors, whose receive function returns a PartialFunction[...], and we can check whether the function isDefinedAt the incoming message.
These are messages that are sent to an actor, but are not handled in the
receivefunction. This only applies to the Scala actors, whosereceivefunction returns aPartialFunction[...], and we can check whether the functionisDefinedAtthe incoming message.