public class TestEvent2 : IEvent
    {
        public int Version { get; }
        public TestObject Obj { get; }

        public TestEvent2(int version, object obj)
        {
            Version = version;
            Obj = ChildTypeConverter.Convert<TestObject>(obj);

        }
    }

    public class TestObject : EventObject
    {
        public string Message { get; set; }
    }