Just like the other delegates so far, we need a new delegate named SODataOfflineStoreRefreshDelegate. In this example it is declared in the same class, so simply set self. This delegate has two mandatory callback methods:
offlineStoreRefreshSucceeded: Called when a refresh has finished successfully.
offlineStoreRefreshFailed: Called when a refresh has failed.
And two optional callback methods:
offlineStoreRefreshStarted: Called when a refresh has started.
offlineStoreRefreshFinished: Called when a refresh has finished.