let start = performance.now();


const task = async (ms,on) => new Promise((resolve, reject)=>setTimeout(()=>resolve(on()),ms));

const on = ()=>console.log(performance.now()-start);


await task(1000,on)

await task(2000,on)

on();

start = performance.now();


const [a, b] = await Promise.all([task(1000,on), task(2000,on)]);

on();

라고 했을때 후자가 당연히 빠른대 반대아님?