Lap button. Please incorporate a function or feature, where the user can push a lap button to record an interval or certain section of their ride. I understand that you can create your own sessions or choose from workouts where this will automatically occur, however this needs to be a  manual function as well. Most importantly include this “button” in the mobile app so that the user can do this remotely from the laptop/pc. 

Make sure you vote up the existing request so Zwift knows what the users want: