Node.js 根据我的测试，为什么在编写Varint代码方面，NodeJS要比Rust快这么多

我用下面两段代码编码Varint，NodeJS大约需要900毫秒，而Rust大约需要2700毫秒.为什么业绩差距这么大？

内存分配看起来更耗时，NodeJS有没有额外的内存分配优化？

NodeJS版本:v20.10.0

Rust版本:1.75.0

JavaScript代码:

// node index.js
const { performance } = require('node:perf_hooks')

function encode_varint(num) {
    let buf_size = 0;
    let cmp_number = num;

    while (cmp_number) {
        cmp_number >>>= 7
        buf_size += 1;
    }

    const buf = new Array(buf_size)
    let temp_num = num;
    let index = 0;

    while (temp_num > 0) {
        if ((temp_num >>> 7) !== 0) {
            buf[index++] = 0x80 | (temp_num & 0x7f)
            temp_num >>>= 7;
        } else {
            buf[index++] = temp_num & 0x7f
            break
        }
    }
    
    return buf;
}
const N = 100_000_000;

const start = performance.now();

for (let i = 0; i < N; i++) {
    const num = 999_999_999_999_999;
    const buf = encode_varint(num);
    // console.log(buf)
}

const end = performance.now();
const elapsed = end - start;
console.log(elapsed);

铁 rust 代码:

// cargo r --release
use std::time;

fn encode_varint(num: usize) -> Vec<u8> {
    let buf_size = {
        let mut size = 1;
        let mut cmp_number = num;
        while cmp_number > 0 {
            cmp_number >>= 7;
            size += 1;
        }
        size
    };
    let mut buf: Vec<u8> = Vec::with_capacity(buf_size);

    let mut temp_num = num;
    while temp_num > 0 {
        if (temp_num >> 7) != 0 {
            buf.push((0x80 | (temp_num & 0x7f)) as u8);
            temp_num >>= 7;
        } else {
            buf.push((temp_num & 0x7f) as u8);
            break;
        }
    }

    buf
}

const N: u32 = 100_000_000;

fn main() {

    let start = time::Instant::now();
    let num = 999_999_999_999_999;

    for _ in 0..N {
        let _buf = encode_varint(num);
        // dbg!(_buf);
    }
    
    let end = time::Instant::now();

    let elapsed = end - start;
    println!("{}", elapsed.as_millis());
}