103 Early Hints
https://httpfox.gay/103
Description
The HTTP 103 Early Hints information response may be sent by a server while it is still
preparing a response, with hints
about the resources that the server is expecting the final response will link.
This allows a browser to start preloading resources even before the server has prepared and sent that final response.
The early hint response is primarily intended for use with the Link header, which indicates the
resources to be loaded.
It may also contain a Content-Security-Policy header that is enforced while processing the
early hint.
A server might send multiple 103 responses, for example, following a redirect. Browsers only
process the first early
hint response, and this response must be discarded if the request results in a cross-origin redirect. Preloaded
resources from the early hint are effectively pre-pended to the Document's head element, and then followed by the
resources loaded in the final response.