FHIR rc Fast Healthcare Interoperability Resources http://hl7-fhir.github.io OperationOutcome types Content Logical Definition http://hl7-fhir.github.io/valueset-operation-outcome.html#definition http://hl7-fhir.github.io/valueset-issue-type.html#definition Extension values https://fhir-ru.github.io/extensibility.html