You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: animation_frame.rs
    path of file: ./repos/winit/src/platform_impl/web/web_sys
    
    the code of the file until where you have to start completion: use std::cell::Cell;
use std::rc::Rc;
use wasm_bindgen::closure::Closure;
use wasm_bindgen::JsCast;

pub struct AnimationFrameHandler {
    window: web_sys::Window,
    closure: Closure<dyn FnMut()>,
    handle: Rc<Cell<Opti
    
    pub fn new(window: web_sys::Window) -> Self {
        let handle = Rc::new(Cell::new(None));
        let closure = Closure::new({
            let handle = handle.clone();
            move || handle.set(None)
        });

        Self {
            window,
            closure,
            handle,
        }
    }