getChildByKey method
Implementation
RenderBox? getChildByKey(Key? key) {
if (key == null) return null;
RenderBox? child = firstChild;
while (child != null) {
final childParentData = child.parentData as _ParentData;
if (childParentData.key == key) {
return child;
}
child = childAfter(child);
}
return null;
}