using System;

using System.Diagnostics;

using System.Threading.Tasks;

​

async Task<int> Task1(){

    await Task.Delay(3000);

    return 5;

}

async Task<int> Task2(){

    await Task.Delay(1000);

    return 2;

}

​

var sw = Stopwatch.StartNew();

​

var (awaitedTask1, awaitedTask2) = (Task1(), Task2());

_ = (await awaitedTask1, await awaitedTask1);

​

sw.Stop();

Console.WriteLine("tuple:" + sw.ElapsedMilliseconds);

​

sw.Restart();

​

var (whenAllTask1, whenAllTask2) = (Task1(), Task2());

_ = await Task.WhenAll(whenAllTask1, whenAllTask2);

​

sw.Stop();

Console.WriteLine("WhenAll:" + sw.ElapsedMilliseconds);