Program2.cs

using System;
using System.IO;
using System.Net.Sockets;
using System.Threading.Tasks;

namespace Sock
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length > 0 && args[0] == "watch")
            {
                Watcher("test.sock");
            }
            else
            {
                Listener("test.sock");
            }
        }

        static void Watcher(string file)
        {
            for (int i = 0; i < 20; i++)
            {
                if (File.Exists(file))
                {
                    WriteAttributes(file);
                }
                Task.Delay(500).Wait();
            }
        }

        static void Listener(string file)
        {
            Socket socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.IP);

            if (File.Exists(file))
            {
                File.Delete(file);
            }

            socket.Bind(new UnixDomainSocketEndPoint(file));
            Console.WriteLine("Bind");
            WriteAttributes(file);
            Task.Delay(1000).Wait();

            socket.Listen(backlog: 10);
            Console.WriteLine("Listen");
            WriteAttributes(file);
            Task.Delay(1000).Wait();

            Task<Socket> task = socket.AcceptAsync();
            Console.WriteLine("Accept");
            WriteAttributes(file);
            Task.Delay(1000).Wait();

            socket.Close();
            Console.WriteLine("Close");
            WriteAttributes(file);
            Task.Delay(1000).Wait();

            File.Delete(file);
        }

        static void WriteAttributes(string file)
        {
            FileAttributes attr = File.GetAttributes(file);
            Console.WriteLine($"{file}: {attr}");
        }
    }
}