detach method Null safety

void detach()

Mark this node as detached.

Typically called only from the parent's detach, and by the owner to mark the root of a tree as detached.

Subclasses with children should override this method to first call their inherited detach method, and then detach all their children.

Implementations of this method should end with a call to the inherited method, as in super.detach().

Implementation

@mustCallSuper
void detach() {
  assert(_owner != null);
  _owner = null;
  assert(parent == null || attached == parent!.attached);
}