dateToString example

        $marketing = $product->getAttribute('marketing');
        if ($marketing instanceof MarketingAttribute) {
            $data['newArticle'] = $marketing->isNew();
            $data['sUpcoming'] = $marketing->comingSoon();
            $data['topseller'] = $marketing->isTopSeller();
        }

        $today = new DateTime();
        if ($product->getReleaseDate() && $product->getReleaseDate() > $today) {
            $data['sReleasedate'] = $this->dateToString($product->getReleaseDate());
            $data['sReleaseDate'] = $data['sReleasedate'];
        }

        return $this->eventManager->filter('Legacy_Struct_Converter_List_Product_Data', $data, [
            'product' => $product,
        ]);
    }

    /** * @param DateTimeInterface|string|null $date */