@CheckReturnValue
    @NonNull
    public static <T> ParallelFlowable<T> from(@NonNull Publisher<? extends T> source,
            int parallelism, int prefetch) {
        ObjectHelper.requireNonNull(source, "source");
        ObjectHelper.verifyPositive(parallelism, "parallelism");
        ObjectHelper.verifyPositive(prefetch, "prefetch");

        return RxJavaPlugins.onAssembly(new ParallelFromPublisher<T>(source, parallelism, prefetch));
    }