Asynchronous Polling Response Messages. At the top of the figure is the response obtained when polling for an asynchronous response when the data is not yet ready. The "redirect" (HTTP 302) header is used to indicate that the client should call a URL (in this case, the same URL). The ellipsis indicate repeated polls of the same URL. When the data is ready, the full response is sent with an HTTP 200 header. Note that the response message is now identical to that of a synchronous service (Figure 4).