src/main/java/io/reactivex/Single.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.CUSTOM)
    public final Single<T> delaySubscription(long time, TimeUnit unit, Scheduler scheduler) {
        return delaySubscription(Observable.timer(time, unit, scheduler));
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.CUSTOM)
    public final Single<T> delaySubscription(long time, TimeUnit unit, Scheduler scheduler) {
        return delaySubscription(Observable.timer(time, unit, scheduler));
    }
Delays the actual subscription to the current Single until the given time delay elapsed.
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code delaySubscription} does by default subscribe to the current Single
on the {@link Scheduler} you provided, after the delay.</dd>
</dl>
@param time the time amount to wait with the subscription
@param unit the time unit of the waiting
@param scheduler the scheduler to wait on and subscribe on to the current Single
@return the new Single instance
@since 2.0