Headless chrome proxy server settings

Could anyone help me with setting proxy-server for headless chrome while using the lighthouse chrome launcher in Node.js as mentioned here

const launcher = new ChromeLauncher({
    port: 9222,
    autoSelectChrome: true, // False to manually select which Chrome install.
    additionalFlags: [
      '--window-size=412,732',
      '--disable-gpu',
      '--proxy-server="IP:PORT"',
      headless ? '--headless' : ''
    ]
  });

However, the above script does not hit my proxy server at all. Chrome seems to fallback to DIRECT:// connections to the target website.

One other resource that talks about using HTTP/HTTPS proxy server in the context of headless chrome is this. But it does not give any example of how to use this from Node.js.

via alpha_cod