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: _549_binary_tree_longest_consecutive_sequence_2.rs
    path of file: ./repos/rustgym/leetcode/src/d5
    
    the code of the file until where you have to start completion: struct Solution;
use rustgym_util::*;

trait Postorder {
    fn postorder(&self, max: &mut usize) -> Option<(i32, usize, usize)>;
}

impl Postorder for TreeLink {
    fn postorder(&self, max: &mut usize) -> Option<(i32, usize, usize)> {
        if let Some(node) = self {
            let node = node.borrow();
            let val = node.val;
            let mut inc = 1;
            let mut dec = 1;
            if let Some((lval, linc, ldec)) = node.left.postorder(max) {
                if lval + 1 == val {
                    inc = inc.max(linc + 1);
                }
                if lval - 1 == val {
                    dec = dec.max(ldec + 1);
                }
       
    
    fn postorder(&self, max: &mut usize) -> Option<(i32, usize, usize)> {
        if let Some(node) = self {
            let node = node.borrow();
            let val = node.val;
            let mut inc = 1;
            let mut dec = 1;
            if let Some((lval, linc, ldec)) = node.left.postorder(max) {
                if lval + 1 == val {
                    inc = inc.max(linc + 1);
                }
                if lval - 1 == val {
                    dec = dec.max(ldec + 1);
                }
            }
            if let Some((rval, rinc, rdec)) = node.right.postorder(max) {
                if rval + 1 == val {
                    inc = inc.max(rinc + 1);
                }
                if rval - 1 == val {
                    dec = dec.max(rdec + 1);
                }
            }
            *max = (*max).max(inc + dec - 1);
            Some((val, inc, dec))
        } else {
            None
        }
    }