Node: prevent repeated `serve()` calls from registering duplicate upgrade handlers

[jakub300]

Describe the feature

crossws/src/server/node.ts

Lines 15 to 27 in 03862fb

	const originalServe = server.serve;
	server.serve = () => {
	server.node?.server!.on("upgrade", (req, socket, head) => {
	ws.handleUpgrade(
	req,
	socket,
	head,
	// @ts-expect-error (upgrade is not typed)
	new NodeRequest({ req, upgrade: { socket, head } }),
	);
	});
	return originalServe.call(server);
	};

Serve in current node code (above) is adding event listeners on every serve call. Incorrect use (multiple serve calls) leads to unexpected behaviour. Repeated serve calls should either do noting or throw exception.

Additional information

• Would you be willing to help implement this feature?