src/main/java/io/reactivex/Completable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Completable retry(long times) {
        return fromPublisher(toFlowable().retry(times));
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Completable retry(long times) {
        return fromPublisher(toFlowable().retry(times));
    }
Returns a Completable that when this Completable emits an error, retries at most the given
number of times before giving up and emitting the last error.
<p>
<img width="640" height="451" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.retry.n.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code retry} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>
@param times the number of times to resubscribe if the current Completable fails
@return the new Completable instance
@throws IllegalArgumentException if times is negative