It is currently impossible to register a generic InvocationCallback<Object> when invoking a method that returns void. This is due to a check that isn't satisfied when the methodReturnType is void. I propose to add the following case
And let the user handle the logic.
I also propose to remove the condition
Which will lead to failure when casting to a return type upon completion. I will provide a PR.
sergey_beryozkin sorry for the confusion.