add method
Implementation
void add(Renderer child) {
assert(child._parent == null);
orderList(_children, child, _getCompareValue);
child
.._parent = this
..tick()
..onMount();
}
void add(Renderer child) {
assert(child._parent == null);
orderList(_children, child, _getCompareValue);
child
.._parent = this
..tick()
..onMount();
}