The advantage of this scenario is that while the requester must still know that some type of polling mechanism is being used, the service itself doesn't.
此方案的优势在于，虽然请求方仍然必须知道使用了某种类型的轮询机制，但服务本身并不必如此。
2
There are already several polling solutions popping up various specifications, so clearly there is a need for this type of solution.
目前存在多个轮询解决方案以及各种规范，这种现象清楚地说明了人们迫切地需要这种类型的解决方案。
3
All server and client implementations MUST support the "long-polling" connection type and SHOULD support "callback-polling". All other connection types are OPTIONAL.