Laravel9 response()->stream() empty result with fwrite()

Question

I need to export huge amount of data as csv string. So I tried to use fopen('php://stdout', w) with fwrite($file, $data). But Laravel response()->stream() do not return anything nor error. I have two wersions. One with fwrite() second with php8 yield. Can somebody explain me please what is the problem? Here is the code.

    public function returnCsv(array $arHeaders, array $arItems)
    {
        $headers = [
            "Content-type" => "text/csv",
            "Content-Disposition" => "attachment; filename=export.csv",
            "Pragma" => "no-cache",
            "Cache-Control" => "must-revalidate, post-check=0, pre-check=0",
            "Expires" => "0",
        ];

        $content = function () use ($arHeaders, $arItems) {
            // Output CSV headers
            yield implode(';', $arHeaders) . PHP_EOL; //using yield to keep the memory low

            // Output CSV data
            foreach ($arItems as $arItem) {
                yield implode(';', $arItem) . PHP_EOL;
            }
        };

        return response()->stream($content, 200, $headers);
    }


    protected function returnCsv2(array $dataHeaders, array $data)
    {
        $headers = [
            "Content-type" => "text/csv",
            "Content-Disposition" => "attachment; filename=export.csv",
            "Pragma" => "no-cache",
            "Cache-Control" => "must-revalidate, post-check=0, pre-check=0",
            "Expires" => "0",
        ];

        $callback = function () use ($dataHeaders, $data) {
            $headersCsv = implode(';', $dataHeaders) . PHP_EOL;

            $stdout = fopen('php://stdout', 'w');

            Log::info($headersCsv);

            fwrite($stdout, $headersCsv);

            // Output CSV data
            foreach ($data as $item) {
                $itemArr = is_array($item) ? $item : $item->toArray();
                $itemCsv = implode(';', $itemArr) . PHP_EOL;
                fwrite($stdout, $itemCsv);
            }

            //fclose($stdout);
        };

        return response()->stream($callback,200, $headers);