Improve the custom hooks chapter

docs/guide/examples/hooks_anti_patterns.rs

@@ -0,0 +1,38 @@
+#![allow(unused)]
+
+use dioxus::prelude::*;
+
+fn main() {}
+
+// ANCHOR: non_clone_state
+use std::cell::RefCell;
+use std::rc::Rc;
+use std::sync::Arc;
+
+struct UseState<'a, T> {
+    value: &'a RefCell<T>,
+    update: Arc<dyn Fn()>,
+}
+
+fn my_use_state<T: 'static>(cx: &ScopeState, init: impl FnOnce() -> T) -> UseState<T> {
+    // The update function will trigger a re-render in the component cx is attached to
+    let update = cx.schedule_update();
+    // Create the initial state
+    let value = cx.use_hook(|| RefCell::new(init()));
+
+    UseState { value, update }
+}
+
+impl<T: Clone> UseState<'_, T> {
+    fn get(&self) -> T {
+        self.value.borrow().clone()
+    }
+
+    fn set(&self, value: T) {
+        // Update the state
+        *self.value.borrow_mut() = value;
+        // Trigger a re-render on the component the state is from
+        (self.update)();
+    }
+}
+// ANCHOR_END: non_clone_state