src/main/java/io/reactivex/Observable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.CUSTOM)
    public final ConnectableObservable<T> replay(final Scheduler scheduler) {
        ObjectHelper.requireNonNull(scheduler, "scheduler is null");
        return ObservableReplay.observeOn(replay(), scheduler);
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.CUSTOM)
    public final ConnectableObservable<T> replay(final Scheduler scheduler) {
        ObjectHelper.requireNonNull(scheduler, "scheduler is null");
        return ObservableReplay.observeOn(replay(), scheduler);
    }
@ CheckReturnValue @ SchedulerSupport ( SchedulerSupport . CUSTOM ) public final ConnectableObservable < T > replay ( final Scheduler scheduler ) { ObjectHelper . requireNonNull ( scheduler , "scheduler is null" ) ; return ObservableReplay . observeOn ( replay ( ) , scheduler ) ; }
Returns a {@link ConnectableObservable} that shares a single subscription to the source ObservableSource that
will replay all of its items and notifications to any future {@link Observer} on the given
{@link Scheduler}. A Connectable ObservableSource resembles an ordinary ObservableSource, except that it does not
begin emitting items when it is subscribed to, but only when its {@code connect} method is called.
<p>
<img width="640" height="445" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.s.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>You specify which {@link Scheduler} this operator will use.</dd>
</dl>

@param scheduler
the Scheduler on which the Observers will observe the emitted items
@return a {@link ConnectableObservable} that shares a single subscription to the source ObservableSource that
will replay all of its items and notifications to any future {@link Observer} on the given
{@link Scheduler}
@see <a href="http://reactivex.io/documentation/operators/replay.html">ReactiveX operators documentation: Replay</a>
Returns a { @link ConnectableObservable } that shares a single subscription to the source ObservableSource that will replay all of its items and notifications to any future { @link Observer } on the given { @link Scheduler } . A Connectable ObservableSource resembles an ordinary ObservableSource except that it does not begin emitting items when it is subscribed to but only when its { @code connect } method is called . <p > <img width = 640 height = 445 src = https : // raw . github . com / wiki / ReactiveX / RxJava / images / rx - operators / replay . o . s . png alt = > <dl > <dt > <b > Scheduler : < / b > < / dt > <dd > You specify which { @link Scheduler } this operator will use . < / dd > < / dl >