The bug here from a year ago said that asyncOpenWithConfiguration should work offline and the fact that it did not was a bug that would be easy to fix.
asyncOpenWithConfiguration never calls its callback for me when the iPhone is in airplane mode. Is this intended behavior?
There is nothing in Realm Objc’s documentation indicating that it will never call back if there is no internet connection. https://realm.io/docs/objc/3.0.2/api/Classes/RLMRealm.html#/c:objc(cs)RLMRealm(cm)asyncOpenWithConfiguration:callbackQueue:callback: