void Render()
{
Console.Write(shown_prompt);
Console.Write(rendered_text);
int max = System.Math.Max(rendered_text.Length + shown_prompt.Length, max_rendered);
for (int i = rendered_text.Length + shown_prompt.Length; i < max_rendered; i++)
Console.Write(' ');
max_rendered = shown_prompt.Length + rendered_text.Length;
// Write one more to ensure that we always wrap around properly if we are at the
// end of a line.
Console.Write(' ');
UpdateHomeRow(max);
}