GUI Repeatbutton up?

Hello, how can I see when my Repeatbutton is not pressed anymore?

Thanks, Andreas.

Something like this:

// C#
bool oldButtonState = false;

if (GUI.RepeatButton(...))
{
    oldButtonState = true
}
else
{
    if (oldButtonState)
    {
        // Button up event
    }
    oldButtonState = false;
}