Function anti_join_into_iter

pub fn anti_join_into_iter<'a, Key, V, Ipos>(
    input_pos: Ipos,
    state_neg: &'a mut FxHashSet<Key>,
    state_pos: &'a mut FxHashSet<(Key, V)>,
    new_tick: bool,
) -> impl 'a + Iterator<Item = (Key, V)>
where
    Key: Eq + Hash + Clone,
    V: Eq + Hash + Clone,
    Ipos: 'a + Iterator<Item = (Key, V)>,