Take action after every WF callback.

def after_each_callback(eng, callback_func, obj):
        """Take action after every WF callback."""
        obj.callback_pos = eng.state.callback_pos
        obj.extra_data["_last_task_name"] = callback_func.__name__
        task_history = get_task_history(callback_func)
        if "_task_history" not in obj.extra_data:
            obj.extra_data["_task_history"] = [task_history]
        else:
            obj.extra_data["_task_history"].append(task_history)