extension_ property
extension_
May be used to represent additional information that is not
part of the basic definition of the element. To make the use of extensions
safe and manageable, there is a strict set of governance applied to the
definition and use of extensions. Though any implementer can define an
extension, there is a set of requirements that SHALL be met as part of the
definition of the extension.
Implementation
@JsonKey(name: 'extension')
List<FhirExtension>? get extension_ => throw _privateConstructorUsedError;