public function addEmbeddedBlobAttachment($content, $filename, $mimeType = null, $options = null, array $notUsed = []) {
		if ($mimeType === null) {
			$ext = pathinfo($filename, PATHINFO_EXTENSION);
			$mimeType = $this->_getMimeByExtension($ext);
		}

		$contentId = null;
		// Deprecated $contentId here
		if (!is_array($options)) {
			$contentId = $options;
			$options = $notUsed;
		}

		$filename = pathinfo($filename, PATHINFO_FILENAME) . '_' . md5($content) . '.' . pathinfo($filename, PATHINFO_EXTENSION);
		if ($contentId === null && ($cid = $this->_isEmbeddedBlobAttachment($content, $filename))) {
			return $cid;
		}

		$options['data'] = $content;
		$options['mimetype'] = $mimeType;
		$options['contentId'] = $contentId ? $contentId : str_replace('-', '', Text::uuid()) . '@' . $this->_domain;
		$file = [$filename => $options];
		$this->addAttachments($file);
		if ($contentId === null) {
			return $options['contentId'];
		}

		// Deprecated
		return $contentId;
	}