src/main/java/io/reactivex/Completable.java
@CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.COMPUTATION)
    public final Completable timeout(long timeout, TimeUnit unit, CompletableSource other) {
        ObjectHelper.requireNonNull(other, "other is null");
        return timeout0(timeout, unit, Schedulers.computation(), other);
    }
@CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.COMPUTATION)
    public final Completable timeout(long timeout, TimeUnit unit, CompletableSource other) {
        ObjectHelper.requireNonNull(other, "other is null");
        return timeout0(timeout, unit, Schedulers.computation(), other);
    }
Returns a Completable that runs this Completable and switches to the other Completable
in case this Completable doesn't complete within the given time.
<p>
<img width="640" height="308" src="https://raw.github.com/wiki/ReactiveX/RxJava/images/rx-operators/Completable.timeout.c.png" alt="">
<dl>
<dt><b>Scheduler:</b></dt>
<dd>{@code timeout} subscribes to the other CompletableSource on
the {@code computation} {@link Scheduler}.</dd>
</dl>
@param timeout the timeout value
@param unit the timeout unit
@param other the other Completable instance to switch to in case of a timeout
@return the new Completable instance
@throws NullPointerException if unit or other is null