extension_ property
extension_
May be used to represent additional information that is not
part of the basic definition of the resource. 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;