Explain the measure and arrange layout cycle in MAUI.

Layout happens in two passes. In Measure, each layout asks children for their desired size given available space. In Arrange, the layout positions each child within the final rectangle it allocates. Custom layouts implement ILayoutManager (Measure and ArrangeChildren). Minimizing invalidations and avoiding deep nesting keeps this cycle cheap.

public class SimpleStackLayoutManager : ILayoutManager
{
    public Size Measure(double widthConstraint, double heightConstraint) { /* ... */ }
    public Size ArrangeChildren(Rect bounds) { /* ... */ }
}