Dart APIunself_local_databaseCollectionDatasystem system property Null safety bool system final Implementation final bool system; unself_local_database unself_local_database CollectionData system property CollectionData class Constructors CollectionData fromJson Properties created createRule deleteRule extra hashCode id listRule name runtimeType system type updated updateRule viewRule Methods copyWith noSuchMethod toColumns toCompanion toJson toJsonString toString Operators operator ==