public function get($fid, $ext = null) {
        $volume = $this->lookup($fid);

        if (!$volume) {
            return null;
        }

        $path = $fid;

        if ($ext) {
            $path = $path . '.' . $ext;
        }

        $res = $this->client->get($this->buildVolumeUrl($volume->getPublicUrl(), $path));

        if ($res->getStatusCode() != 200) {
            throw new SeaweedFSException('Unexpected response when retrieving file: ' . $res->getStatusCode());
        }

        return $res->getBody()->detach();
    }