public function output(string $mime)
    {
        // Nothing to output, the webserver will handle it
        if ($this->xsendfile)
            return;

        $bytes = readfile($this->filename);
        if (!empty($this->length) && $bytes != $this->length)
        {
            self::getLogger()->warning(
                "FileResponse promised to send {0} bytes but {1} were actually transfered of file {2}", 
                [$this->length, $bytes, $this->output_filename]
            );
        }
    }