* - optional: (bool) If set and truthy, the field may be left empty
* - sensitive: (bool) If set and truthy, the field is considered sensitive. Code using the
* request should avoid exposing the value of the field.
+ * - skippable: (bool) If set and truthy, the client is free to hide this
+ * field from the user to streamline the workflow. If all fields are
+ * skippable (except possibly a single button), no user interaction is
+ * required at all.
*
* All AuthenticationRequests are populated from the same data, so most of the time you'll
* want to prefix fields names with something unique to the extension/provider (although