Function iron_shapes_booleanop::connect_edges::filter_events

fn filter_events<T, Ctr, P, ContributesToResultFn>(
    sorted_events: &[Rc<SweepEvent<T, Ctr, P>>],
    contributes_to_result: ContributesToResultFn
) -> Vec<Rc<SweepEvent<T, Ctr, P>>>where
    T: CoordinateType + Debug,
    ContributesToResultFn: Fn(&SweepEvent<T, Ctr, P>) -> bool,

Take all the events that contribute to the result. This depends on the boolean operation to be performed. Also adjusts the prev pointers for hole attribution.