[Use Case]: Support `Flow.Publisher` return type

[hantsy]

As a ...

• Application user/user of the configuration itself
• API user (application developer)
• SPI user (container or runtime developer)
• Specification implementer

I need to be able to ...

The asynchronous/concurrency case should accept Flow.Publisher<T> or Flow.Publisher<Void> and Kotlin Coroutines suspend as the return type. In the background, it should configure the default executor to run the tasks and also allow to choose which executor service to run.

As Spring, when using JDK Flow or reactiestreams API, no need @Asynchronous

Which enables me to ...

Which can add ReactiveStream support.

Additional information

See Spring WebFlux, also worked in classic Scheduled, EventLisenter:

• https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/scheduling/annotation/Scheduled.html