src/Response/File.php
protected function extractFileName(){
        foreach (explode("\r\n", $this->headers) as $header)
        {
            if (strpos($header, 'filename') !== false && strpos($header, 'Content-Disposition') !== false)
            {
                $fileName = substr($header, (strpos($header, "=")+1));
                $this->setFileName($fileName);
                break;
            }
        }
    }
protected function extractFileName(){
        foreach (explode("\r\n", $this->headers) as $header)
        {
            if (strpos($header, 'filename') !== false && strpos($header, 'Content-Disposition') !== false)
            {
                $fileName = substr($header, (strpos($header, "=")+1));
                $this->setFileName($fileName);
                break;
            }
        }
    }
Extract the filename from the Headers, and store it in filename property