ThreadStatic demo

ThreadStaticDemo.cs

using System;
using System.Threading;
using System.Threading.Tasks;

namespace ThreadStaticDemo
{
    public class Program
    {
        public static void Main(string[] args)
        {
            PrintDescription("Before assignment");
            SomeScope.ScopeDescription = "Desc01";
            PrintDescription("After assignment");

            Task.Run(() =>
            {
                PrintDescription("Before assignment");
                SomeScope.ScopeDescription = "Desc02";
                PrintDescription("After assignment");
            }).GetAwaiter().GetResult();

            Console.WriteLine("Press a key...");
            Console.ReadLine();
        }

        static void PrintDescription(string message)
        {
            Console.WriteLine($"{message} [Thread: {Thread.CurrentThread.ManagedThreadId}]: " + (SomeScope.ScopeDescription ?? "[null]"));
        }
    }

    public class SomeScope
    {
        // Try commenting the attribute out and see the difference
        [ThreadStatic]
        public static string ScopeDescription;
    }
}