Why not just send the data too along with the UUID? It'll save another roundtrip in case of scenario B right? Or do you have data to prove that scenario B is a

Why not just send the data too along with the UUID? It'll save another roundtrip in case of scenario B right? Or do you have data to prove that scenario B is a lot less likely to occur, making it sensible to save bandwidth by not re-transmitting the data?