beforeUpdate method
Called immediately before a value is updated.
This method can be used to perform actions or validations before a state change occurs. It is called after the decision to update the value has been made but before the internal state is actually modified.
Parameters:
oldValue: The current value before the updatenewValue: The proposed new value for the update
Implementation
@override
void beforeUpdate(T oldValue, T newValue) {
print("Before update: $oldValue -> $newValue");
}