System.Diagnostics.TextWriterTraceListener.WriteLine C# (CSharp) Method

        public override void WriteLine(string message) { }
    }

        static void Main(string[] args)
        {
            var directory = args.Length == 0 ? "." : args[0];
            directory = directory.EndsWith("\\") ? directory : directory + "\\";
            TextWriterTraceListener log = null;
            try
            {
                using (var filestream = new FileStream(directory + "log.csv", FileMode.Create, FileAccess.Write, FileShare.Read))
                {
                    log = new TextWriterTraceListener(filestream);
                    foreach (var file in new DirectoryInfo(directory).GetFiles().Select(file => file.Name))
                    {
                        var begin = DateTime.Now;

                        using (var source = new Bitmap(Image.FromFile(file)))
                        {
                            using (var bm = ConvertToGrayscale(source))
                            {
                                bm.Save(string.Format("{0}{1}.{2}", directory, "gray", file));
                            }
                        }
                        var end = DateTime.Now;
                        log.WriteLine(string.Format("{0},gray.{0},{1}", file, end - begin));
                        log.Flush();
                    }
                }

            }
            catch (Exception ex)
            {
                log.WriteLine(ex.Message);
                log.WriteLine(ex.StackTrace);
            }
        }