WebTransport: пример кода

// Establish a session (server must speak HTTP/3 + WebTransport).
const wt = new WebTransport('https://example.com:4433/rt');
await wt.ready;

// --- Unreliable datagrams: newest-wins state, latency over guarantees ---
const writer = wt.datagrams.writable.getWriter();
writer.write(encodePosition(player)); // may be dropped — that's fine, we send 60/s

const reader = wt.datagrams.readable.getReader();
while (true) {
  const { value, done } = await reader.read();
  if (done) break;
  applyPosition(decode(value)); // gaps are expected and acceptable
}

// --- Reliable stream: must-arrive data, native backpressure ---
const stream = await wt.createBidirectionalStream();
const w = stream.writable.getWriter();
await w.write(new TextEncoder().encode('must not be lost')); // awaits on backpressure

// Server-opened streams arrive as an async iterable.
for await (const incoming of wt.incomingUnidirectionalStreams) {
  readFully(incoming); // each is independent — no HOL blocking between them
}

wt.closed.then(() => reconnect()); // you still own reconnect logic