builder property
final
Called to build children on demand.
Implementors of RenderTwoDimensionalViewport.layoutChildSequence call this builder to create the children of the viewport. For ChildVicinity indices greater than maxXIndex or maxYIndex, null will be returned by the default build implementation. This default behavior can be changed by overriding the build method.
Must return null if asked to build a widget with a ChildVicinity that does not exist.
The delegate wraps the children returned by this builder in RepaintBoundary widgets if addRepaintBoundaries is true.
Implementation
final TwoDimensionalIndexedWidgetBuilder builder;