Execution (via ExecController.fork()).Execution (via ExecController.fork()).Operation into a Flux.Promise into an Flux.Promise for an iterable into an Flux.fork(reactor.core.publisher.Flux<T>) that allows access to the registry of the forked execution inside an Action.forkEach(reactor.core.publisher.Flux<T>) that allows access to the registry of each forked execution inside an Action.Hooks.onOperatorError(BiFunction) with Reactor that provides a default error handling strategy of forwarding exceptions to the execution error handler.Promise into a Mono.Flux into a Promise, for all of the observable's items.Mono into a Promise, for the mono's single item.Flux into a Publisher, for all of the observable's items.