How to stream a procedurally generated level?

I am relatively new to Unity (working through an online course currently) and am trying to understand how to go about streaming a procedurally generated level (3D). I would like to generate a large interior when the user begins a new game, however I am not sure how I would then be able to stream said generated level.

As I understand it, to stream levels you have to break up your map into sections that can then be loaded in and out relative to the player's position. However, if the level is procedurally generated on a new game start, then I am not sure how I could then grid the map out for streaming since it's all in runtime. Is there some way to build in the streaming logic before the map generates, or a way to do so after a map is generated? Any guidance on this would be very appreciated.