getFields method
Inquiry method that can be used to read the "Field List" specified for this Subscription.
Lifecycle This method can only be called if the Subscription has been initialized using a "Field List".
Returns the "Field List" to be subscribed to through the server, or null if the Subscription was initialized with a "Field Schema" or was not initialized at all.
Implementation
List<String>? getFields() {
return _fields?.toList();
}