I think there is a bug in the logout callback, when using it with Kotlin.
The error is:
Caused by: java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull, parameter payload
[...]
at com.auth0.android.provider.LogoutManager.resume(LogoutManager.java:55)
at com.auth0.android.provider.WebAuthProvider.resume(WebAuthProvider.java:531)
at com.auth0.android.provider.AuthenticationActivity.deliverAuthenticationResult(AuthenticationActivity.java:129)
at com.auth0.android.provider.AuthenticationActivity.onResume(AuthenticationActivity.java:90)
at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1446)
at android.app.Activity.performResume(Activity.java:7939)
It looks like the error is that LogoutManager.resume(LogoutManager.java:55) is called like this callback.onSuccess(null); but the BaseCallback.void onSuccess(T payload); is specified as non null.
The stack trace points to this line in the LogoutManager class, which is calling the callback’s onSuccess with null because you were just logged out successfully (and there’s nothing to pass you down the callback). I guess the Void type in Kotlin expects it to have a value other than null, or else it would have been marked as optional in the interface declaration. Is that something you can do or it doesn’t let you? I’d try:
Use Void? instead on the VoidCallback implementation