ThreadInitialization.cs

using System.Threading;
using Xunit;
using Xunit.Abstractions;

namespace Blog.Threading
{
    public class ThreadInitialization
    {
        private readonly ITestOutputHelper _testOutputHelper;

        public ThreadInitialization(ITestOutputHelper testOutputHelper)
        {
            _testOutputHelper = testOutputHelper;
        }

        void Secondary()
        {
            for (int i = 0; i < 1000; i++) _testOutputHelper.WriteLine($"Ping from {nameof(Secondary)}");
        }

        [Fact]
        void Thread_initialization_Thread_Start()
        {
            var t = new Thread(Secondary);
            t.Start();
            for (int i = 0; i < 1000; i++) _testOutputHelper.WriteLine("Ping from Mai!");
        }

        
        [Fact]
        void Thread_initialization_Thread_Pool()
        {
            ThreadPool.QueueUserWorkItem(_ => Secondary());
            for (int i = 0; i < 1000; i++) _testOutputHelper.WriteLine("Ping from Main");
        }
    }
}