lekoala / silverstripe-mailgun

            $tags = explode(',', $tagsHeader->getValue());

            $message->getHeaders()->remove('X-MC-Tags');

        }

        if ($message->getHeaders()->has('X-MC-Metadata')) {

            $metadataHeader = $message->getHeaders()->get('X-MC-Metadata');

            $metadata = json_decode($metadataHeader->getValue(), JSON_OBJECT_AS_ARRAY);

            $message->getHeaders()->remove('X-MC-Metadata');

        }

        if ($message->getHeaders()->has('X-MC-InlineCSS')) {

            $inlineCss = $message->getHeaders()->get('X-MC-InlineCSS')->getValue();

            $message->getHeaders()->remove('X-MC-InlineCSS');

            $message->getHeaders()->remove('X-Mailgun-Tag');

        }

        // @link https://documentation.mailgun.com/en/latest/user_manual.html#attaching-data-to-messages

        if ($message->getHeaders()->has('X-Mailgun-Variables')) {

            $metadataHeader = $message->getHeaders()->get('X-Mailgun-Variables');

            $metadata = json_decode($metadataHeader->getValue(), JSON_OBJECT_AS_ARRAY);

            $message->getHeaders()->remove('X-Mailgun-Variables');

        }

        // Build recipients

        $primaryEmail = null;