test manoli.net/csharpformat/

not pastebin, but generates colored HTML

using System.IO;
public void Main() 
{
    // READWRITE - User::result
    string msg = string.Format("\tsome result {0}", variable);
    Dts.Variables["User::result"].Value = Dts.Variables["User::result"].Value.ToString() + msg;
    Log(msg);
}
private void Log(string str, params object[] pars) 
{
    bool fireAgain = false;
    Dts.Events.FireInformation(1, "control", string.Format(str, pars), "", 0, ref fireAgain);
}