Function create_selector 

pub fn create_selector<F, Out>(derived: F) -> StateHandle<Out>
where
    F: Fn() -> Out + 'static,
    Out: PartialEq + 'static,

Creates a memoized value from some signals. Also know as “derived stores”. Unlike create_memo, this function will not notify dependents of a change if the output is the same. That is why the output of the function must implement PartialEq.

To specify a custom comparison function, use create_selector_with.