fork(rx.Observable<T>) that allows access to the registry of the forked execution inside an Action.forkEach(rx.Observable<T>) that allows access to the registry of each forked execution inside an Action.RxJavaObservableExecutionHook with RxJava that provides a default error handling strategy of forwarding exceptions to the execution error handler.Promise into an Observable.Operation into an Observable.Promise for an iterable into an Observable.Observable into a Promise, for all of the observable's items.Observable into a Promise, for all of the observable's items.Observable into a Promise, for the observable's single item.Observable into a Promise, for the observable's single item.Observable into a Publisher, for all of the observable's items.Observable into a Publisher, for all of the observable's items.Execution (via ExecController.fork()).Execution (via ExecController.fork()).