[racket] I'd use an object for this in PHP, how do I handle it in racket?

I'm making an API wrapper for the WebDriver wire protocol:
http://code.google.com/p/selenium/wiki/JsonWireProtocol#Command_Detail

In general all of the API calls require me to pass back to the server a
token (:sessionId in the spec) that is unique to the current instance. In
PHP or some "other" language I would create the wrapper as an object, and
store the token in a private property. I know racket has full support for
classes and objects, but using an object here doesn't feel like racket's
style. 

How do I write it without using an object? What is best practice?

If it matters I'm likely to have 10-100 instances / threads of this
running in parallel at a time... as many as I can fit on a machine.

Shalom,
Jordan