I'm working on an app which can quickly generate quite a lot of data. Like 10+GB per session! One thing I've seen is a new kind of lightning attached storage. There are several little dongles available. As an example https://www.amazon.com/Authorized-connector-Reader-iPhone5S-i-easy/dp/B00RRQSJ44 But there are a bunch of other on amazon and elsewhere. I'd like to be able to support 'external storage' using these devices. Is that possible? Every single one seems to be coming with their own app. Can a device only be seen by an app from the same vendor? thanks!