reactor-core/src/main/java/reactor/core/publisher/ConnectableFlux.java
public final Flux<T> refCount(int minSubscribers, Duration gracePeriod) {
		return refCount(minSubscribers, gracePeriod, Schedulers.parallel());
	}
public final Flux<T> refCount(int minSubscribers, Duration gracePeriod) {
		return refCount(minSubscribers, gracePeriod, Schedulers.parallel());
	}
Connects to the upstream source when the given number of {@link org.reactivestreams.Subscriber} subscribes.
Disconnection can happen in two scenarios: when the upstream source completes (or errors) then
there is an immediate disconnection. However, when all subscribers have cancelled,
a <strong>deferred</strong> disconnection is scheduled. If any new subscriber comes
in during the {@code gracePeriod} that follows, the disconnection is cancelled.

<p>
<img class="marble" src="doc-files/marbles/refCountWithMinSubscribersAndGracePeriod.svg" alt="">

@param minSubscribers the number of subscribers expected to subscribe before connection
@param gracePeriod the {@link Duration} for which to wait for new subscribers before actually
disconnecting when all subscribers have cancelled.

@return a reference counting {@link Flux} with a grace period for disconnection