/// Construct an empty `PathFiller`
Construct an empty `PathFiller`
Construct an empty ` PathFiller `
fn empty() -> Self {
        PathFiller {
            queue: VecDeque::new(),
        }
    }
fn empty ( ) -> Self { PathFiller { queue : VecDeque :: new ( ) , } }
Construct an empty `PathFiller`
Construct an empty ` PathFiller `