I read a bit about http2 versus http3 and the main thing I learnt is that h3 will use QUIC which in turns uses UDP. From what I remember, the main difference between UDP and TCP is that TCP is able to check data integrity and ask the client to resend the data if they are corrupted. As this seems a pretty important aspect, I'm wondering how h3 can simply switch to UDP. How is the data integrity ensured then?
HTTP/3 uses the QUIC Transport Protocol, which in turn sits on top of UDP. It is the QUIC protocol that ensures reliable delivery.