Scatter gather Async Flux example using #ProjectReactor

sample.java

// Create an async message-passing Processor exposing a Flux API
TopicProcessor<String> sink = TopicProcessor.create();

// Scatter Gather the input sequence
sink
  .map(String::toUpperCase)
  .flatMap(s -> 
      Mono.fromCallable(() -> someRepository.findOneByCategory(s))
          .timeout(Duration.ofSeconds(3), someRepository::fallback)
          .subscribeOn(Schedulers.parallel())
  )
  .subscribe(System.out::println);

// Sink values asynchronously
sink.onNext("Rx");
sink.onNext("ReactiveStreams");
sink.onNext("ReactiveStreamsCommons");
sink.onNext("RingBuffer");

//Shutdown and clean async resources
sink.onComplete();