pub trait MangleCache: Send + Sync {
// Required methods
fn vars_cache(&self, op: &mut dyn FnMut(&FxHashMap<Id, Atom>));
fn props_cache(&self, op: &mut dyn FnMut(&FxHashMap<Atom, Atom>));
fn update_vars_cache(&self, new_data: &FxHashMap<Id, Atom>);
fn update_props_cache(&self, new_data: &FxHashMap<Atom, Atom>);
}