public function getPartStreamFilterManagerFactory()
    {
        if ($this->partStreamFilterManagerFactory === null) {
            $this->partStreamFilterManagerFactory = new PartStreamFilterManagerFactory(
                $this->getStreamFactory()
            );
        }
        return $this->getInstance(
            'partStreamFilterManagerFactory',
            __NAMESPACE__ . '\Message\Part\PartStreamFilterManagerFactory'
        );
    }