Fix PersistentWatcher not working with NamespaceFacade

[kezhuw]

NamespaceFacade does not support getCuratorListenable while #520 use it to listen for CuratorEventType.CLOSING to fix CURATOR-729.

This commit exports CuratorFrameworkBase::client to retrieve underlying framework client to listen for for CuratorEventType.CLOSING.

Fixes #1259.

[Copilot]

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (1)

curator-recipes/src/main/java/org/apache/curator/framework/recipes/watch/PersistentWatcher.java:85

• Directly casting the client to CuratorFrameworkBase could lead to a ClassCastException if the client is not an instance of CuratorFrameworkBase. Consider adding an instance check or clarifying that the client must be of that type.

((CuratorFrameworkBase) client).client().getCuratorListenable().addListener(((ignored, event) -> {

[kezhuw]

I think we probably could introduce Runnable listenEvent(CuratorListener listener) in long term to deprecate Listenable<CuratorListener> getCuratorListenable(). This way we gain more control over implementation. I see no semantics reason to forbide NamespaceFacade::getCuratorListenable.

[tisonkun]

Thanks for taking care of this! LGTM.