reactor-core/src/main/java/reactor/core/publisher/Flux.java
public final Flux<T> doOnSubscribe(Consumer<? super Subscription> onSubscribe) {
		Objects.requireNonNull(onSubscribe, "onSubscribe");
		return doOnSignal(this, onSubscribe, null, null, null, null, null, null);
	}
public final Flux<T> doOnSubscribe(Consumer<? super Subscription> onSubscribe) {
		Objects.requireNonNull(onSubscribe, "onSubscribe");
		return doOnSignal(this, onSubscribe, null, null, null, null, null, null);
	}
public final Flux < T > doOnSubscribe ( Consumer < ? super Subscription > onSubscribe ) { Objects . requireNonNull ( onSubscribe , "onSubscribe" ) ; return doOnSignal ( this , onSubscribe , null , null , null , null , null , null ) ; }
Add behavior (side-effect) triggered when the {@link Flux} is subscribed.
<p>
This method is <strong>not</strong> intended for capturing the subscription and calling its methods,
but for side effects like monitoring. For instance, the correct way to cancel a subscription is
to call {@link Disposable#dispose()} on the Disposable returned by {@link Flux#subscribe()}.
<p>
<img class="marble" src="doc-files/marbles/doOnSubscribe.svg" alt="">

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

@return an observed  {@link Flux}
Add behavior ( side - effect ) triggered when the { @link Flux } is subscribed . <p > This method is <strong > not< / strong > intended for capturing the subscription and calling its methods but for side effects like monitoring . For instance the correct way to cancel a subscription is to call { @link Disposable#dispose () } on the Disposable returned by { @link Flux#subscribe () } . <p > <img class = marble src = doc - files / marbles / doOnSubscribe . svg alt = >