You aren’t allowed to control the origin header from inside the web browser sandbox as per the standard, hence why a web browser javascript library doesn’t expose such an option. 
The origin header is to control web browser security, if you are in native code then you could easily just scrape a webpage to get a token (potentially even grabbing the web browsers cookie or whatever else) and then feed that in to the live websocket, so none of that security matters anyway for native code (hence why you should build a proper auth system if you need auth regardless, but the browser should be able to store that auth in a cookie backed by an origin as that is the way the standard was written).
