src/main/java/io/reactivex/Observable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Observable<T> repeat(long times) {
        if (times < 0) {
            throw new IllegalArgumentException("times >= 0 required but it was " + times);
        }
        if (times == 0) {
            return empty();
        }
        return RxJavaPlugins.onAssembly(new ObservableRepeat<T>(this, times));
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Observable<T> repeat(long times) {
        if (times < 0) {
            throw new IllegalArgumentException("times >= 0 required but it was " + times);
        }
        if (times == 0) {
            return empty();
        }
        return RxJavaPlugins.onAssembly(new ObservableRepeat<T>(this, times));
    }
Returns an Observable that repeats the sequence of items emitted by the source ObservableSource at most
{@code count} times.
<p>
<img width="640" height="336" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/repeatCount.o.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code repeat} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>

@param times
the number of times the source ObservableSource items are repeated, a count of 0 will yield an empty
sequence
@return an Observable that repeats the sequence of items emitted by the source ObservableSource at most
{@code count} times
@throws IllegalArgumentException
if {@code count} is less than zero
@see <a href="http://reactivex.io/documentation/operators/repeat.html">ReactiveX operators documentation: Repeat</a>