private void doHandle(JRTConfigSubscription<ConfigInstance> sub, JRTClientConfigRequest jrtReq, Connection connection) {
        if (sub.isClosed()) return; // Avoid error messages etc. after closing

        boolean validResponse = jrtReq.validateResponse();
        log.log(FINE, () -> "Response " + (validResponse ? "valid" : "invalid") + ". Req: " + jrtReq + "\nSpec: " + connection);
        Trace trace = jrtReq.getResponseTrace();
        trace.trace(TRACELEVEL, "JRTConfigRequester.doHandle()");
        log.log(FINEST, trace::toString);
        if (validResponse)
            handleOKRequest(jrtReq, sub);
        else
            handleFailedRequest(jrtReq, sub, connection);
    }
Requests the config for the {@link com.yahoo.config.ConfigInstance} on the given {@link ConfigSubscription}

@param sub a subscription
config/src/main/java/com/yahoo/config/subscription/impl/JRTConfigRequester.java