using System;

using System.Diagnostics;

using System.Threading.Tasks;

​

public class Program

{

    public static async Task Main()

    {

        var (result1, elapsed1) = await TimeConsumingMethod1().GetElapsedTimeAsync();

        Console.WriteLine($"Elapsed time1: {elapsed1}");

        var (result2, elapsed2) = await TimeConsumingMethod2().GetElapsedTimeAsync();

        Console.WriteLine($"Elapsed time1: {elapsed2}");

    }

​

    private static async Task<int> TimeConsumingMethod1()

    {

        var t = 5000;

        await Task.Delay(t);

        return t;

    }

​

    private static async Task<int> TimeConsumingMethod2()

    {

        var t = 3000;

        await Task.Delay(t);

        return t;

    }

}

​

public static class SwExtensions

{

    public static (T, long) GetElapsedTime<T>(Func<T> action)

    {

        T result;

        var sw = new Stopwatch();

        sw.Start();

        try

        {

            result = action();

        }

        finally

        {

            sw.Stop();

        }

​

        return (result, sw.ElapsedMilliseconds);

    }

​

    public static async Task<(T, long)> GetElapsedTimeAsync<T>(this Task<T> asyncAction)

    {

        T result;

        var sw = new Stopwatch();

        sw.Start();

        try

        {

            result = await asyncAction;

        }

        finally

        {

            sw.Stop();

        }

​

        return (result, sw.ElapsedMilliseconds);

    }

}