What is the best way to implement C#'s BackgroundWorker in Delphi?

private void button1_Click(object sender, EventArgs e)
{
  BackgroundWorker bg = new BackgroundWorker();
  bg.DoWork += new DoWorkEventHandler(bg_DoWork);
  bg.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bg_RunWorkerCompleted);
  test_number++;
  object[] arguments = { "test", test_number };
  bg.RunWorkerAsync(arguments);
}

void bg_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
      // done.
}

void bg_DoWork(object sender, DoWorkEventArgs e)
{
     // do actual work here
}