Determine keyboard position relative to MSMessagesAppViewController

I am trying to adjust my content layout to accomodate the keyboard opening in MSMessagesAppViewController. I can't find anyway to determine where on the screen the MSMessageAppViewController is. UIWindow:convertRect:toWindow:NULL and UIAccessibilityConvertFrameToScreenCoordinates(self.view.bounds,self.view) both show the top at 0. But, there is actually a 64 pixel height area owned by iMessage above my view. Anyone know how to find that number? I was thinking topLayoutGuide contained that info, but it is 0 in iOS 10.