create node watcher API

packages/native-core/src/node_watcher.rs

@@ -0,0 +1,15 @@
+use crate::{node::FromAnyValue, NodeMut};
+
+/// A trait for watching for changes in the DOM tree.
+pub trait NodeWatcher<V: FromAnyValue + Send + Sync> {
+    /// Called after a node is added to the tree.
+    fn on_node_added(&self, _node: NodeMut<V>) {}
+    /// Called before a node is removed from the tree.
+    fn on_node_removed(&self, _node: NodeMut<V>) {}
+    /// Called after a node is moved to a new parent.
+    fn on_node_moved(&self, _node: NodeMut<V>) {}
+    // /// Called after the text content of a node is changed.
+    // fn on_text_changed(&self, _node: NodeMut<V>) {}
+    // /// Called after an attribute of an element is changed.
+    // fn on_attribute_changed(&self, _node: NodeMut<V>, attribute: &str) {}
+}