src/main/java/io/reactivex/Completable.java
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Completable retry(BiPredicate<? super Integer, ? super Throwable> predicate) {
        return fromPublisher(toFlowable().retry(predicate));
    }
@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Completable retry(BiPredicate<? super Integer, ? super Throwable> predicate) {
        return fromPublisher(toFlowable().retry(predicate));
    }
Returns a Completable that retries this Completable in case of an error as long as the predicate
returns true.
<p>
<img width="640" height="325" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.retry.ff.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code retry} does not operate by default on a particular {@link Scheduler}.</dd>
</dl>
@param predicate the predicate called when this emits an error with the repeat count and the latest exception
and should return true to retry.
@return the new Completable instance