Connect through proxy to signalr HUB - nodejs

Trying to connect to SignalR Hub through the nodejs client via a Proxy. The connection doesn't work with a corporate proxy. What should I put in options(aka IHttpConnectionOptions) in my nodejs client to get it to work ?

const signalR = require('@microsoft/signalr');
var url = require('url');
var HttpsProxyAgent = require('https-proxy-agent');
var agent;

// HTTP/HTTPS proxy to connect to
var proxy = process.env.http_proxy;
if (proxy) {
var options = url.parse(proxy);
agent = new HttpsProxyAgent(options);
}
let options = {
accessTokenFactory: pcsUtils.getJwtToken,
Proxy: agent//????????????
}
connection = new signalR.HubConnectionBuilder()
.withUrl(hubUrl, options)
.build();
It works without the proxy.

TIA,