You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: _1080_insufficient_nodes_in_root_to_leaf_paths.rs
    path of file: ./repos/rustgym/leetcode/src/d10
    
    the code of the file until where you have to start completion: struct Solution;
use rustgym_util::*;

trait Postorder {
    fn postorder(self, limit: i32) -> TreeLink;
}

impl Postorder for TreeLink {
    fn postorder(self, limit: i32) -> TreeLink {
        if let Some(node) = self {
            let val = node.borrow_mut().val;
            let left = node.borrow_mut().left.take();
            let right = node.borrow_mut().right.take();
            if left.is_none() && right.is_none() {
                if val >= limit {
                    Some(node)
                } else {
                    None
                }
         
    
fn test() {
    let root = tree!(
        1,
        tree!(
            2,
            tree!(4, tree!(8), tree!(9)),
            tree!(-99, tree!(-99), tree!(-99))
        ),
        tree!(
            3,
            tree!(-99, tree!(12), tree!(13)),
            tree!(7, tree!(-99), tree!(14))
        )
    );
    let limit = 1;
    let res = tree!(
        1,
        tree!(2, tree!(4, tree!(8), tree!(9)), None),
        tree!(3, None, tree!(7, None, tree!(14)))
    );
    assert_eq!(Solution::sufficient_subset(root, limit), res);
    let root = tree!(
        5,
        tree!(4, tree!(11, tree!(7), tree!(1)), None),
        tree!(8, tree!(17), tree!(4, tree!(5), tree!(3)))
    );
    let limit = 22;
    let res = tree!(
        5,
        tree!(4, tree!(11, tree!(7), None), None),
        tree!(8, tree!(17), tree!(4, tree!(5), None))
    );
    assert_eq!(Solution::sufficient_subset(root, limit), res);
    let root = tree!(1, tree!(2, tree!(-5), None), tree!(-3, tree!(4), None));
    let limit = -1;
    let res = tree!(1, None, tree!(-3, tree!(4), None));
    assert_eq!(Solution::sufficient_subset(root, limit), res);
}