@CheckReturnValue
    @NonNull
    @BackpressureSupport(BackpressureKind.ERROR)
    @SchedulerSupport(SchedulerSupport.NONE)
    public final <U> Flowable<T> sample(Publisher<U> sampler) {
        ObjectHelper.requireNonNull(sampler, "sampler is null");
        return RxJavaPlugins.onAssembly(new FlowableSamplePublisher<T>(this, sampler, false));
    }