addChild method
Implementation
void addChild(RenderBox child) {
if (_renderLayoutBox != null) {
RenderLayoutBox? scrollingContentBox = _renderLayoutBox!.renderScrollingContent;
if (scrollingContentBox != null) {
scrollingContentBox.add(child);
} else {
_renderLayoutBox!.add(child);
}
} else if (_renderReplaced != null) {
_renderReplaced!.child = child;
}
}