static void Main(string[] args)
        {
            string filePath = @"C:\Users\s0163726\source\repos\IO_lab03\IO_lab03\pliczek.txt";
            FileStream fs = new FileStream(filePath, FileMode.Open);
            byte[] data = new byte[1024];
            var ar = fs.BeginRead(data, 0, 1024, null, new { Data = data, Stream = fs });
            fs.EndRead(ar);
            Console.WriteLine(ASCIIEncoding.ASCII.GetString(data).Substring(0, 1024));

            for (int i = 0; i < 100000; i++)
                for (int j = 0; j < 100000; j++)
                    temp = i * j;
        }