@Override
    public Map<ConfigKey<ConfigInstance>, ConfigInstance> config() {
        Map<ConfigKey<ConfigInstance>, ConfigInstance> ret = new HashMap<>();
        handles.forEach((k, v) -> {
            ConfigInstance config = v.getConfig();
            if (config == null) {
                throw new IllegalArgumentException("Got a null config from the config system for key: " + k +
                        "\nConfig handle: " + v);
            }
            ret.put(k, config);
        });
        return ret;
    }
@author gjoranv
@author Tony Vaagenes
@author ollivir
container-core/src/main/java/com/yahoo/container/di/CloudSubscriber.java