src/main/java/io/reactivex/Observable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.COMPUTATION)
    public final <R> Observable<R> replay(Function<? super Observable<T>, ? extends ObservableSource<R>> selector, int bufferSize, long time, TimeUnit unit) {
        return replay(selector, bufferSize, time, unit, Schedulers.computation());
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.COMPUTATION)
    public final <R> Observable<R> replay(Function<? super Observable<T>, ? extends ObservableSource<R>> selector, int bufferSize, long time, TimeUnit unit) {
        return replay(selector, bufferSize, time, unit, Schedulers.computation());
    }
@ CheckReturnValue @ SchedulerSupport ( SchedulerSupport . COMPUTATION ) public final < R > Observable < R > replay ( Function < ? super Observable < T > , ? extends ObservableSource < R > > selector , int bufferSize , long time , TimeUnit unit ) { return replay ( selector , bufferSize , time , unit , Schedulers . computation ( ) ) ; }
Returns an Observable that emits items that are the results of invoking a specified selector on items
emitted by a {@link ConnectableObservable} that shares a single subscription to the source ObservableSource,
replaying no more than {@code bufferSize} items that were emitted within a specified time window.
<p>
Note that due to concurrency requirements, {@code replay(bufferSize)} may hold strong references to more than
{@code bufferSize} source emissions.
<p>
<img width="640" height="350" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/replay.o.fnt.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>This version of {@code replay} operates by default on the {@code computation} {@link Scheduler}.</dd>
</dl>

@param <R>
the type of items emitted by the resulting ObservableSource
@param selector
a selector function, which can use the multicasted sequence as many times as needed, without
causing multiple subscriptions to the ObservableSource
@param bufferSize
the buffer size that limits the number of items the connectable ObservableSource can replay
@param time
the duration of the window in which the replayed items must have been emitted
@param unit
the time unit of {@code time}
@return an Observable that emits items that are the results of invoking the selector on items emitted by
a {@link ConnectableObservable} that shares a single subscription to the source ObservableSource, and
replays no more than {@code bufferSize} items that were emitted within the window defined by
{@code time}
@see <a href="http://reactivex.io/documentation/operators/replay.html">ReactiveX operators documentation: Replay</a>
Returns an Observable that emits items that are the results of invoking a specified selector on items emitted by a { @link ConnectableObservable } that shares a single subscription to the source ObservableSource replaying no more than { @code bufferSize } items that were emitted within a specified time window . <p > Note that due to concurrency requirements { @code replay ( bufferSize ) } may hold strong references to more than { @code bufferSize } source emissions . <p > <img width = 640 height = 350 src = https : // raw . github . com / wiki / ReactiveX / RxJava / images / rx - operators / replay . o . fnt . png alt = > <dl > <dt > <b > Scheduler : < / b > < / dt > <dd > This version of { @code replay } operates by default on the { @code computation } { @link Scheduler } . < / dd > < / dl >