An object that can be used to signal a connection error to Scrivito from inside the index callback.

If you encounter some problem inside your connection callback (e.g. an HTTP 4xx response from the backend), and you want to communicate this issue to the user, you can resolve the callback by means of a DataConnectionError instance to communicate the error to the user. It will then be made available to your app as a DataScopeError via DataScope#getError().