Wait.ForCondition - how to use

[Wit]

I can't find anywhere examples for Wait.ForCondition.
I would like my test to wait for input box to contain text longer than 4 characters.
How to do it?

[Wit]

I think I found some old WebAii documentation that pointed me in the right direction:

private bool TextBoxHasTextLonger(ArtOfTest.WebAii.Controls.Control control,  object length)
{
    HtmlInputText textBox = (HtmlInputText)control;
    return textBox.Text.Length>(int)length;
}

[Test]
public void Test1()
{

    Manager.LaunchNewBrowser();
    ActiveBrowser.NavigateTo("http://www.skyscanner.net");

    SearchPanel sp= Find.ById<SearchPanel>("searchcontrols");
    sp.Departure.TypeText("rzes", 100);
    Desktop.KeyBoard.KeyPress(Keys.Tab); // to leave the box and fire autosuggest completion


    sp.Destination.TypeText("lond", 100);
    Desktop.KeyBoard.KeyPress(Keys.Tab); // to leave the box and fire autosuggest completion

    // wait 5s for autocomplete to fire; text should be longer than typed 4 characters
    sp.Destination.Wait.ForCondition(TextBoxHasTextLonger, false, 4, 5000);

    sp.SearchButton.Click();
}