src/main/java/io/reactivex/flowables/ConnectableFlowable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
    public final Flowable<T> refCount(int subscriberCount) {
        return refCount(subscriberCount, 0, TimeUnit.NANOSECONDS, Schedulers.trampoline());
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    @BackpressureSupport(BackpressureKind.PASS_THROUGH)
    public final Flowable<T> refCount(int subscriberCount) {
        return refCount(subscriberCount, 0, TimeUnit.NANOSECONDS, Schedulers.trampoline());
    }
Connects to the upstream {@code ConnectableFlowable} if the number of subscribed
subscriber reaches the specified count and disconnect if all subscribers have unsubscribed.
<dl>
<dt><b>Backpressure:</b></dt>
<dd>The operator itself doesn't interfere with backpressure which is determined by the upstream
{@code ConnectableFlowable}'s backpressure behavior.</dd>
<dt><b>Scheduler:</b></dt>
<dd>This {@code refCount} overload does not operate on any particular {@link Scheduler}.</dd>
</dl>
<p>History: 2.1.14 - experimental
@param subscriberCount the number of subscribers required to connect to the upstream
@return the new Flowable instance
@since 2.2