Dart APIunself_modelFlataddMissingKeys addMissingKeys property Null safety bool addMissingKeys Implementation bool get addMissingKeys; unself_model unself_model Flat addMissingKeys property Flat class Constructors Flat fromJson Properties addMissingKeys copyWith definition entityPath extra fieldMap hashCode includePath key name runtimeType Methods map mapOrNull maybeMap maybeWhen noSuchMethod toJson toString when whenOrNull Operators operator ==