ActorCallbackSetters.mapHandle(mapper: ActorHandleMapper<TContextData>): ActorCallbackSetters<TContextData>
Sets the callback function that maps a WebFinger username to the corresponding actor's internal handle. If it's omitted, the handle is assumed to be the same as the WebFinger username, which makes your actors have the immutable handles. If you want to let your actors change their fediverse handles, you should set this dispatcher.
mapper: ActorHandleMapper<TContextData>
ActorCallbackSetters<TContextData>