public void stop() {
        executorService.shutdown();
        try {
            executorService.awaitTermination(SHUTDOWN_TIMEOUT, TimeUnit.SECONDS);
        } catch (InterruptedException e) {
            Thread.interrupted(); // Ignore and continue shutdown.
        }
        delayedConfigResponses.stop();
        fileServer.close();
        supervisor.transport().shutdown().join();
        isRunning = false;
    }
Returns a String with statistics data for the server.

@param req a Request
configserver/src/main/java/com/yahoo/vespa/config/server/rpc/RpcServer.java