readonly type: 'Attempted' | 'Sent' | 'UnexpectedResponse' | 'ResponseReady' | 'Notified' | 'NotifyOverweight' | 'NotifyDispatchError' | 'NotifyDecodeFailed' | 'InvalidResponder' | 'InvalidResponderVersion' | 'ResponseTaken' | 'AssetsTrapped' | 'VersionChangeNotified' | 'SupportedVersionChanged' | 'NotifyTargetSendFail' | 'NotifyTargetMigrationFail';