attachTo method
Attaches an object instance to this state.
Implementation
@mustCallSuper
void attachTo(Object instance) {
assert(
_instanceAttached == null,
"Can't attach a new instance because an instance is already.\n"
"Use `detachInstance` method, if you want to attach a new instance.",
);
Reactter.one(instance, Lifecycle.destroyed, _onInstanceDestroyed);
_instanceAttached = instance;
}