public static FluentLayout Below(this UIView view, UIView previous, nfloat?margin = null) => view.Top().EqualTo().BottomOf(previous).Plus(margin.GetValueOrDefault(DefaultMargin));
public static FluentLayout WithSameTop(this UIView view, UIView previous) => view.Top().EqualTo().TopOf(previous);
public static FluentLayout AtTopOf(this UIView view, UIView parentView, nfloat?margin = null) => view.Top().EqualTo().TopOf(parentView).Plus(margin.GetValueOrDefault(DefaultMargin));