public void stop() {
        LOG.info("Shutting down Zuul.");
        serverGroup.stop();
        LOG.info("Completed zuul shutdown.");
    }
Use {@link #Server(Registry, ServerStatusManager, Map, ClientConnectionsShutdown, EventLoopGroupMetrics,
EventLoopConfig)}
instead.
zuul-core/src/main/java/com/netflix/zuul/netty/server/Server.java