public static IEnumerator <WaitCommand> FadeOut(this IScreenFader fader, IClock clock, FaderSettings faderSettings)
 {
     return(FadeOut(clock, faderSettings, value => fader.Opacity = value));
 }
 public static IEnumerator <WaitCommand> FadeIn(IClock clock, FaderSettings faderSettings, Action <float> fader)
 {
     return(Fade(clock, faderSettings.FadeInDuration, Routines.EaseInOutAnimation.Reverse(), fader));
 }