Push notifications for IOS support for custom data

Well, AdvancedPlatformDelivery is working for iOS on my title now, but still custom data isn't supported there.

Since we have finite resources, we do have to prioritize what work the team is doing. That prioritization is not based on when something is added to the backlog, but rather by the impact it will have for our customers. That's based on two things, primarily - the overall plan for the service (for example, no one specifically asked for LiveOps capabilities - it's just something we saw as a major gap for many developers) and how many developers are asking for a given feature. In this case, we haven't heard from many folks that this is a priority, so it's not something we'll be scheduling anytime soon.