php下载大一点的zip文件下载不全

Question

       //下载zip包
        $url = dirname($url) . '/' .$str_name['filename'] . '.zip';
        $origin_size = get_headers($url,(bool)1);
        $origin_size = $origin_size['Content-Length']??0;


        $ch = curl_init($url);
        //设置抓取的url
        $dir = $upload_dir.'/' . $file_name;
        $fp = fopen($dir, "wb");
        curl_setopt($ch, CURLOPT_FILE, $fp);
        curl_setopt($ch, CURLOPT_HEADER, 0);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
        $content = curl_exec($ch);
        curl_close($ch);
        fclose($fp);

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