长时间轮询：也就是所谓的异步轮询，这种方式是纯服务器端推送方式和客户端拉取方式的混合。

Long Polling: Also known as Asynchronous Polling, this method is a hybrid of pure server push and client pull.

youdao

长时间轮询：也就是所谓的异步轮询，这种方式是纯服务器端推送方式和客户端拉取方式的混合。

Long Polling: Also known as Asynchronous Polling, this method is a hybrid of pure server push and client pull.

youdao