How can I start / stop a request stream with node.js?

I have

return request({
  method: "POST",
  url: response.stream.url,
  json: true,
  forever: true,
  body: {
    sessionid: response.stream.sessionid,
    symbols: symbolParams
  }
}).on("data", onData)

That gives me data whenever it comes through. But what if I want to STOP listening on that stream, how can I do that?