using System;

using System.Linq;

using System.Threading;

using System.Threading.Tasks;

​

public class Program

{

    static readonly AsyncLocal<(int logicalId, int parentThreadId)> Context = new();

​

    // Pay attention that even this static property which is called from different threads at runtime pull the runtime copy of Context

    static string ContextAsString => $"Context: (logicalId: {Context.Value.logicalId}, parentThreadId {Context.Value.parentThreadId})";

​

    static async Task Main()

    {

        await Task.WhenAll(

            Enumerable.Range(1, 5)

            .Select(

                i =>

                {

                    return Task

                        .Run(async () =>

                        {

                            // Forcing current thread to let go

                            await Task.Yield();

                            // Set the context

                            Context.Value = (i, Thread.CurrentThread.ManagedThreadId);

                            Console.WriteLine($"[Original Thread] {ContextAsString}");

​

                            // Start a new thread

                            await Task

                            .Run(async () =>

                            {

                                // Forcing current thread to let go

                                await Task.Yield();

                                Console.WriteLine($"[Child Thread] ID: {Thread.CurrentThread.ManagedThreadId}, {ContextAsString}");

                            })

                            // Continue it with another task

                            .ContinueWith(async _ =>

                            {

                                // Forcing current thread to let go

                                await Task.Yield();

                                Console.WriteLine($"[Continuation Thread] ID: {Thread.CurrentThread.ManagedThreadId}, {ContextAsString}");

                            })

                            .Unwrap();

                        });

                }));

    }

}