Proxy websocket requests being intercepted by hmr server

[mspero]

I am trying to configure a proxy for http and websocket requests. It seems http requests are intercepted correctly by the proxy server, websocket requests however are not intercepted and the ws open requests remains pending forever. I've tracked the issue in the serverPluginHmr.js file. It seems the websocket server for hmr is handling the ws upgrade request but doing nothing since the request header 'sec-websocket-protocol' does not match 'vite-hmr'.