ASExtensionLocalizedFailureReasonErrorKey
A key that specifies a string value to show to the user when a request fails.
Declaration
let ASExtensionLocalizedFailureReasonErrorKey: StringDiscussion
When canceling a request, your extension calls cancelRequest(withError:). The system informs the user that the request failed. To show additional information regarding the failure, use this key to set a string value in the error’s userInfo dictionary.