attach method
- covariant Object owner
Mark this layer as attached to the given owner.
Typically called only from the parent's attach method, and by the
owner
to mark the root of a tree as attached.
Subclasses with children should override this method to
attach all their children to the same owner
after calling the inherited method, as in super.attach(owner)
.
Implementation
@mustCallSuper
void attach(covariant Object owner) {
assert(_owner == null);
_owner = owner;
}