Reports subscribe() calls in "reactive" methods.

Methods returning a Publisher type (including Flux and Mono) should not call the subscribe() method directly because it can break the reactive call chain.

Instead of using subscribe(), consider using composition operators like flatMap(), zip(), then(), and so on.

Example:

  Flux<String> stringFlux(){
    Flux<String> flux = Flux.just("abc");
    flux.subscribe(); // <- blocking 'subscribe' call in non-blocking context
    return flux;
  }