TPL with one worker

Output.txt

Main thread: 1

Worker thread: 1

Worker thread: 1
Worker thread: 4
Worker thread: 5
Worker thread: 6
Worker thread: 5
Worker thread: 4
Worker thread: 3

Program.cs

using System;
using System.Threading.Tasks;


class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine($"Main thread: {Environment.CurrentManagedThreadId}");
        Action action = () => Console.WriteLine($"Worker thread: {Environment.CurrentManagedThreadId}");

        Console.WriteLine();
        Parallel.Invoke(action);

        Console.WriteLine();
        Parallel.Invoke(action, action, action, action, action, action, action);

    }
}