code: public boolean unsubscribe(Request req, long timeout) {
      initErrorInfo();
  
      return endSubscription(req, timeout, parent.getProxyHost() != null, "Unsubscribe");
    }
docs: This method is the same as unsubscribe(eventId, timeout) except that instead of creating the
  SUBSCRIBE request from parameters passed in, the given request message parameter is used for
  sending out the SUBSCRIBE message if the subscription is active.
  <p>
  The Request parameter passed into this method should come from calling createSubscribeMessage()
  - see that javadoc. The event "id" in the given request will be used subsequently for error
  checking the SUBSCRIBE response and NOTIFY request from the server.