public function sendBody() { if ($this->binary !== null
) { return $this->
sendBodyByBinary();
} if ($this->file !== null
) { return $this->
sendBodyByFilePath();
} throw DownloadException::
forNotFoundDownloadSource();
} /**
* output download text by file.
*
* @return DownloadResponse
*/
private function sendBodyByFilePath() {