Inform Metrics class that experience collection is done.

def end_experience_collection_timer(self):
        """
        Inform Metrics class that experience collection is done.
        """
        if self.time_start_experience_collection:
            curr_delta = time() - self.time_start_experience_collection
            if self.delta_last_experience_collection is None:
                self.delta_last_experience_collection = curr_delta
            else:
                self.delta_last_experience_collection += curr_delta
        self.time_start_experience_collection = None