iMessage active conversation consistently nil

I am building an iMessage app in iOS 10 with Swift.

I am trying to get the active conversation in iMessage. I feel like I'm overlooking something simple. I have this line copied and pasted in just about every possible function in my MSMessagesAppViewController:

print(self.activeConversation)

Every time I get nil.

This happens when running on device and in simulator. I have even tried a brand new xcode project to make sure I didnt break something, still no luck. Is there something I'm supposed to be doing to get permission to access this?