pub type EventHandler<D> = Option<Rc<EventHandlerNonNull<D>>>;Aliased Type§
pub enum EventHandler<D> {
    None,
    Some(Rc<EventHandlerNonNull<D>>),
}pub type EventHandler<D> = Option<Rc<EventHandlerNonNull<D>>>;pub enum EventHandler<D> {
    None,
    Some(Rc<EventHandlerNonNull<D>>),
}