Got it. I have another question. Say a new user opts in to receive a text notification over the phone but you don't know whether they're using iMessage, or an iPhone for that matter. Can you try sending them an iMessage via your API as an attempt, and then handle failure (instead of "iMessage turned off", the case is: "not on an iPhone"... perhaps they're on Android, landline, etc). Also if so, does your API differentiate between the two cases? And any commentary about privacy and how you all handle that would be great.