Remoting

On the client code here: https://github.com/triploc/ib-sdk/blob/master/doc/remoting.md

```
var io = require('socket.io-client')('http://localhost:8080'),
    session = sdk.proxy(io);
    
session.service.relay(socket);
```

what is "socket" in `session.service.relay(socket)`?  thanks!