void serviceAdded(ServiceConfig cfg) {
        if (serviceAdded) {
            return;
        }
        serviceAdded = true;
        final Server server = cfg.server();
        server.addListener(new ServerListenerAdapter() {
            @Override
            public void serverStarted(Server server) {
                serverHealth.setHealthy(true);
            }

            @Override
            public void serverStopping(Server server) {
                // NOT_SERVING will be sent to clients by changing a healthiness of a server
                serverHealth.setHealthy(false);
                synchronized (watchers) {
                    watchers.values().forEach(StreamObserver::onCompleted);
                    watchers.clear();
                }
            }
        });
    }
Returns a new builder which builds a new {@link GrpcHealthCheckService}.
grpc/src/main/java/com/linecorp/armeria/server/grpc/GrpcHealthCheckService.java