Since there is no Comet standard as such, let's distinguish between two types of Comet implementations: long-polling and streaming.

因为不存在Comet的标准，让我们区别来看两种不同类型的Comet实现：长轮询与流式查询。

youdao

All server and client implementations MUST support the "long-polling" connection type and SHOULD support "callback-polling". All other connection types are OPTIONAL.

所有服务端和客户端实现必须支持“长轮询”连接类型，并且应该支持“回调轮询”。其他连接类型都是可选的。

youdao

Another common technique is long polling.

另一个常见的技巧是长轮询。

youdao

Andy Kohut, who directs the Pew Center for the People and the Press, has looked at long-term polling and finds that sentiment has been slowly growing for a change of direction.

NPR: Conservatively Speaking, Things Look Bad

And recent polling data indicate that once a long-shot candidate, Pollak is steadily closing in on Schakowsky's lead.

CENTERFORSECURITYPOLICY: Republicans, Democrats & Israel

And that doesn't really have much of an effect, I imagine, on today's polling data, but it does have an effect on our long-term economic viability.

WHITEHOUSE: Press Briefing