(unhandledMessage: StringAdd).self
(unhandledMessage: StringFormat).self
(unhandledMessage: ArrowAssoc[UnhandledMessage]).x
(Since version 2.10.0) Use leftOfArrow
instead
(unhandledMessage: Ensuring[UnhandledMessage]).x
(Since version 2.10.0) Use resultOfEnsuring
instead
This message is published to the EventStream whenever an Actor receives a message it doesn't understand