pub fn tab<IF, I, T, KF, K, VF, V>( active_fn: impl Fn() -> usize + 'static, each_fn: IF, key_fn: KF, view_fn: VF, ) -> Tab<T>where IF: Fn() -> I + 'static, I: IntoIterator<Item = T>, KF: Fn(&T) -> K + 'static, K: Eq + Hash + 'static, VF: Fn(T) -> V + 'static, V: IntoView + 'static, T: 'static,