/run js
const f1 = async (sec) => {
return new Promise((resolve) => {
setTimeout(() => { resolve(); }, sec * 100);
});
}

const f = async (sec1, sec2, message) => {
await f1(sec1);
console.log(message, "timing 1", new Date());
await f1(sec2);
console.log(message, "timing 2", new Date());
};

(async () => {
console.log("start", new Date());
await Promise.all([f(1, 2, "first_"), f(2, 2, "second")]);
console.log("finish", new Date());
})();