private void PrintGoal(string eventName, Goal goal)
{
sb.Append(eventName);
sb.Append(new string (' ', goal.Level * 4));
SolutionTreePrinter.Print(goal, sb);
sb.AppendLine();
}
void IDebugEventSink.Visit(Enter enter)
{
var sb = new StringBuilder();
var goal = enter.Node.HeadGoal;
sb.Append(new string (' ', goal.Level * 4));
SolutionTreePrinter.Print(goal, sb);
listView1.Items.Add(sb.ToString());
}