Dart APIunself_modelArchiveSchemaread read method Null safety ArchiveData read(Map<String, dynamic> json ) Implementation ArchiveData read(Map<String, dynamic> json) { throw UnimplementedError(); } unself_model unself_model ArchiveSchema read method ArchiveSchema class Constructors ArchiveSchema fromJson Properties appId constraint copyWith created extra hashCode id part runtimeType updated version Methods noSuchMethod read toJson toString Operators operator ==