How to get all assets used by a level?

I’d like to be able to download assets as needed, that part is easy. However what would be the easiest way to query all assets required for a level before loading that level?

I’d hate to manually keep track of every asset I use in a level.

My goal is to have players only download the content / assets for the specific map they want to play on, so I can keep the initial download minimal.

I know I could create a ue4 project for each map, and then just keep track of all assets in a project while moving them to a master project, but it seems a little involved?