Send email on order status update

Would it be possible to add functionality to send an email when the order status is updated from Fulfillment to Completed (in other words, upon successful completion of the "fulfill" workflow transition).

I found a similar issue for the Drupal 7 version of this module, using Rules, but the Rules integration for Commerce 2 is severely lacking and therefore it doesn't appear that solution would apply for this requested use-case.

Thanks!