public function writeComma($space = true)
    {
        try {
            $this->getStream()->write(',');
            if ($space === true) {
                $this->writeSpace();
            }
        } catch (StreamException $e) {
            $msg = "An error occured while writing a comma (,).";
            throw new StreamAccessException($msg, $this, 0, $e);
        }
    }