lekoala / silverstripe-mailgun

        // Mandrill compatibility

        // Data is merge with transmission and removed from headers

        // @link https://mandrill.zendesk.com/hc/en-us/articles/205582467-How-to-Use-Tags-in-Mandrill

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

            $tagsHeader = $message->getHeaders()->get('X-MC-Tags');

            $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);

        // Handle mailgun headers

        // Data is merge with message and removed from headers

        // @link https://documentation.mailgun.com/en/latest/user_manual.html#sending-via-smtp

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

            $tagsHeader = $message->getHeaders()->get('X-Mailgun-Tag');

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

            $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');