CompletableFuture<List<Endpoint>> endpoints() {
        return queryInstances()
                .thenApply(response -> {
                    requireNonNull(response.data, "Response data cannot be null");
                    requireNonNull(response.data.hosts, "Response data.hosts cannot be null");
                    return response.data.hosts.stream()
                                              .map(QueryInstancesClient::toEndpoint)
                                              .filter(Objects::nonNull)
                                              .collect(toImmutableList());
                });
    }
A Nacos client that is responsible for
<a href="https://nacos.io/en-us/docs/v2/guide/user/open-api.html">Nacos Open-Api - Query instances</a>.
nacos/src/main/java/com/linecorp/armeria/internal/nacos/QueryInstancesClient.java