@SuppressWarnings("rawtypes")
    public static void setOnMaybeAssembly(@Nullable Function<? super Maybe, ? extends Maybe> onMaybeAssembly) {
        if (lockdown) {
            throw new IllegalStateException("Plugins can't be changed anymore");
        }
        RxJavaPlugins.onMaybeAssembly = onMaybeAssembly;
    }