Missing Stage types

[akarnokd]

Looks like some of the ReactiveStreamsFactory based sources do not have a Stage equivalent:

• empty -> could be mimicked with Stage.Of returning an empty collection, but less efficient
• of(T) -> could be mimicked with Stage.Of returning an empty collection, but less efficient
• of(T...) -> could be mimicked with Stage.Of returning an empty collection, but less efficient
• iterate -> could be mimicked with Stage.Of, but less efficient
• generate -> could be mimicked with Stage.Of, but less efficient
• forEach
• ignore -> there is a Stage.Cancel though
• reduce(T, BinaryOperator) -> there is FindFirst though
• reduce(BinaryOperator)
• collect(Supplier, BiConsumer) -> there is Collect with java.util.stream.Collector though
• toList -> could be mimicked via Collect, but it is inefficient in
• to(SubscriberBuilder) -> is this Stage.SubscriberStage too, ignoring the CompletionStage?
• via(ProcessorBuilder) -> is this Stage.ProcessorStage too?

[Azquelt]

To fill out the rest of your list with what the core implementation does:

• forEach -> uses Stage.Collect
• ignore -> same as forEach but with an empty action
• reduce -> implements the reduction operation as a Collector and uses Stage.Collect
• to(SubscriberBuilder) / via(ProcessorBuilder) -> these don't have a corresponding stage. Instead the stages from the SubscriberBuilder or ProcessorBuilder are added to the graph. The core implementation actually creates an internal nested stage which is removed when toGraph() is called.

You're correct that there isn't a 1:1 mapping between builder methods and stages. I'm not sure why that decision was taken.