addAllItems method
Implementation
List<dynamic> addAllItems(List<dynamic> resultItems) {
// this node may have items as well as subnodes (since items may not
// be wholely contained in any single subnode
resultItems.addAll(this.items);
for (int i = 0; i < 4; i++) {
if (subnode[i] != null) {
subnode[i]!.addAllItems(resultItems);
}
}
return resultItems;
}