请教老师解释一下这些指标，他们是瞬时值还是累加值。

route_upstream_model_consumer_metric_llm_duration_count:
route_upstream_model_consumer_metric_llm_first_token_duration:
route_upstream_model_consumer_metric_llm_service_duration:
route_upstream_model_consumer_metric_llm_stream_duration_count: