@SuppressWarnings("unchecked")
    @CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.NONE)
    public static <T> Observable<T> ambArray(ObservableSource<? extends T>... sources) {
        ObjectHelper.requireNonNull(sources, "sources is null");
        int len = sources.length;
        if (len == 0) {
            return empty();
        }
        if (len == 1) {
            return (Observable<T>)wrap(sources[0]);
        }
        return RxJavaPlugins.onAssembly(new ObservableAmb<T>(sources, null));
    }