using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        Foo F = new Foo();

        F.Run("A");

        F.Run("B");

        FooStatic.Run("C");

        FooStatic.Run("D");

        FooStaticChild.Run("E");

    }

}

​

public class Foo

{

    public async void Run(string s)

    {

        Console.WriteLine(s);

        Console.WriteLine(Bar.AsyncLocalVar);

        await Bar.DoSOmeAsync();

        Console.WriteLine(Bar.AsyncLocalVar);

        Console.WriteLine();

    }   

}

​

public class FooStatic

{

    public async static void Run(string s)

    {

        Console.WriteLine(s);

        Console.WriteLine(Bar.AsyncLocalVar);

        await Bar.DoSOmeAsync();

        Console.WriteLine(Bar.AsyncLocalVar);

        Console.WriteLine();

    }   

}

​

public class FooStaticChild

{

    public async static void Run(string s)

    {

        Console.WriteLine(s);

        Console.WriteLine(Bar.AsyncLocalVar);

        await Bar.DoSomeChildWork();

        Console.WriteLine(Bar.AsyncLocalVar);

        Console.WriteLine();

    }   

}

​

public static class Bar

{

    private static Random rnd = new Random();

    private static AsyncLocal<int?> asyncLocalVar = new AsyncLocal<int?>();

    public static int AsyncLocalVar

    {

        get => asyncLocalVar.Value ?? rnd.Next(1,99);

        set => asyncLocalVar.Value = new int?(value);

    }

​

    public static Task DoSOmeAsync()

    {

        AsyncLocalVar = rnd.Next(1,10);

        Console.WriteLine(AsyncLocalVar);

        var bb = Task.FromResult("aaaa");

​

        return bb;

    }

    public static Task DoSomeChildWork()

    {

        AsyncLocalVar = rnd.Next(1,10);

        Console.WriteLine(AsyncLocalVar);

        BarChild.DoSomeWork();

        var bb = Task.FromResult("aaaa");

​

        return bb;

    }

}

​

public static class BarChild

{

    public static void DoSomeWork()

    {

        Console.WriteLine("Child Work");

        Console.WriteLine(Bar.AsyncLocalVar);   

    }

}