private void update() {
        if (isClosing()) {
            return;
        }

        nacosClient.endpoints()
                   .handleAsync((endpoints, cause) -> {
                       if (isClosing()) {
                           return null;
                       }

                       if (cause != null) {
                           logger.warn("Unexpected exception while fetching the registry from: {}",
                                       nacosClient.uri(), cause);
                       } else {
                           setEndpoints(endpoints);
                       }

                       scheduledFuture = eventLoop.schedule(this::update, registryFetchIntervalMillis,
                                                            TimeUnit.MILLISECONDS);
                       return null;
                   }, eventLoop);
    }
Returns a newly-created {@link NacosEndpointGroupBuilder} with the specified {@code nacosUri}
and {@code serviceName} to build {@link NacosEndpointGroupBuilder}.

@param nacosUri the URI of Nacos API service, including the path up to but not including API version.
                (example: http://localhost:8848/nacos)
nacos/src/main/java/com/linecorp/armeria/client/nacos/NacosEndpointGroup.java