builder property

Called to build children for the sliver.

Will be called only for indices greater than or equal to zero and less than childCount (if childCount is non-null).

Should return null if asked to build a widget with a greater index than exists.

May result in an infinite loop or run out of memory if childCount is null and the builder always provides a zero-size widget (such as Container() or SizedBox.shrink()). If possible, provide children with non-zero size, return null from builder, or set a childCount.

The delegate wraps the children returned by this builder in RepaintBoundary widgets.