Simplest Console File Logger (Files)

DoSomething.cs

public class DoSomething
{
    public void Work(string p1)
    {
        //... doing heavy work

        Main.Log("Heavy work done with result", "SUCCESS");

    }

    public void MoreWork(string p2)
    {
        //... doing heavy work

        Main.Log("More work done with result", "SUCCESS");

    }

}

Parameter.cs

public class Parameter
{
    public string Param1 = "";
    public string Param2 = "";
}

Program.cs

using System.Text;

// TOP-LEVEL ARGUMENTS
Main.Start(args);


// MAIN MODULE
static public class Main {

    static Parameter PARAMETER = new Parameter();

    static StringBuilder LOGDATA = new StringBuilder();

    static public void Start(string[] args)
    {
        //Process Arguments
        foreach (string arg in args)
        {
            var a = arg.Split(':');
            switch (a[0].ToUpper())
            {
                case "PARAM1": PARAMETER.Param1 = a[1]; break;
                case "PARAM2": PARAMETER.Param1 = a[1]; break;
                default: break;
            }
        }

        DoSomething ds = new DoSomething();
        ds.Work(PARAMETER.Param1);
        ds.MoreWork(PARAMETER.Param2);

        HandleEnd();
    }

    public static void Log(params string[] args)
    {
        var msg = string.Join(" ", args).TrimEnd();
        Console.WriteLine(msg);
        LOGDATA.AppendLine(msg);
    }

    static void HandleEnd()
    {
        if (LOGDATA.Length > 0)
        {
            string logFile = $"{DateTime.Now.ToString("u").Replace(":","-")}.log";
            string logFilePath = Path.Combine(Environment.CurrentDirectory, logFile);
            StreamWriter logStream = new StreamWriter(logFilePath, true, Encoding.UTF8);
            logStream.Write(LOGDATA);
            logStream.Close();
        }
    }

}