@Override
    public final <T> T get(IClientConfigKey<T> key) {
        Optional<T> value = (Optional<T>)internalProperties.get(key);
        if (value == null) {
            if (!isDynamic) {
                return null;
            } else {
                set(key, null);
                value = (Optional<T>) internalProperties.get(key);
            }
        }

        return value.orElse(null);
    }
Register an action that will refresh the cached value for key. Uses the current value as a reference and will
update from the dynamic property source to either delete or set a new value.

@param key - Property key without client name or namespace
ribbon-core/src/main/java/com/netflix/client/config/ReloadableClientConfig.java