public function send($output, OutputStrategyInterface $outputStrategy = null)
    {
        if (!($outputStrategy instanceof OutputStrategyInterface)) {
            $outputStrategy = $this->defaultOutputStrategy;
        }

        $contentType = new Header(
            Header::CONTENT_TYPE,
            $outputStrategy->getMime()
        );

        $this->header($contentType);

        return $outputStrategy->send($output);
    }