Instancing Rust Structs in JS and maintaining a list of them in Rust

pub struct Rect {
    pub top: Cell<u32>,
    pub left: Cell<u32>,
}

impl Resource for Rect {
    fn name(&self) -> Cow<str> {
        Cow::Borrowed("rect")
    }
}

impl GarbageCollected for Rect {}

#[op2]
impl Rect {
    #[fast]
    #[getter]
    pub fn top(&self) -> u32 {
        self.top.get()
    }

    #[fast]
    #[getter]
    pub fn left(&self) -> u32 {
        self.left.get()
    }
    #[fast]
    pub fn top(&self, top: u32) {
        self.top.set(top);

    }

    #[fast]
    pub fn sleft(&self, left: u32) {
        self.left.set(left);
    }
}

let rects: Vec<Arc<Mutex<Rect>>>

#[op2]
#[cppgc]
fn op_create_rect(
    state: &mut OpState,
    top: u32,
    left: u32,
) -> Result<Arc<Mutex<Rect>>, JsErrorBox> {
    let rect = Arc::new(Mutex::new(Rect {
        top: Cell::new(top),
        left: Cell::new(left),
    }));

    rects.push(rect.clone());

    Ok(rect.clone())
}