@CheckReturnValue
    @SchedulerSupport(SchedulerSupport.NONE)
    public final Observable<T> repeatWhen(final Function<? super Observable<Object>, ? extends ObservableSource<?>> handler) {
        ObjectHelper.requireNonNull(handler, "handler is null");
        return RxJavaPlugins.onAssembly(new ObservableRepeatWhen<T>(this, handler));
    }