WebTransport: ментальная модель

WebTransport over HTTP/3 (QUIC): multiple independent streams + unreliable datagrams. «WebSocket on QUIC» с выбором reliability per message.

Разбор

WebSocket — single ordered reliable stream on TCP. One lost packet — TCP HOL stalls everything behind retransmit.

WebTransport for HTTP/3 on QUIC (UDP). QUIC — many independent streams; loss on A doesn't block B. Bidirectional/unidirectional streams + datagrams not retried/ordered.

WebSocket (TCP):   [====== one ordered reliable stream ======]  ← 1 lost packet stalls all
WebTransport(QUIC):[ stream 1 ][ stream 2 ][ stream 3 ]         ← independent, no HOL block
                   + datagrams: •  •   •      •   •              ← unreliable, unordered, lowest latency

Mental upgrade: reliability and ordering — per message choice, not connection property.

Итог

WebTransport wins high-rate apps needing HOL-free streams or UDP-like datagrams; WebSocket simpler for basic duplex chat.