I don't think UDP should be regarded as an optimization you add later. If you leave it to add after you've written the rest of your networking code, changing fr

I don't think UDP should be regarded as an optimization you add later. If you leave it to add after you've written the rest of your networking code, changing from ordered reliable delivery to unordered unreliable delivery is going to have a pretty profound effect, which you probably will want to have thought about from the start.