reactor-core/src/main/java/reactor/core/publisher/Flux.java
public final Flux<T> doOnNext(Consumer<? super T> onNext) {
		Objects.requireNonNull(onNext, "onNext");
		return doOnSignal(this, null, onNext, null, null, null, null, null);
	}
public final Flux<T> doOnNext(Consumer<? super T> onNext) {
		Objects.requireNonNull(onNext, "onNext");
		return doOnSignal(this, null, onNext, null, null, null, null, null);
	}
Add behavior (side-effect) triggered when the {@link Flux} emits an item.
<p>
<img class="marble" src="doc-files/marbles/doOnNextForFlux.svg" alt="">

@param onNext the callback to call on {@link Subscriber#onNext}

@reactor.errorMode This operator supports {@link #onErrorContinue(BiConsumer) resuming on errors}
(including when fusion is enabled). Exceptions thrown by the consumer are passed to
the {@link #onErrorContinue(BiConsumer)} error consumer (the value consumer
is not invoked, as the source element will be part of the sequence). The onNext
signal is then propagated as normal.

@return an observed  {@link Flux}