resource-hints | Resource Hints | Awesome List library

I have a site, that uses a 302 redirect for new visitors to establish a new session. I've created a demo of the basic flow on my personal site:

1. https://crenshaw.dev/redirect/index.php (302)
2. https://crenshaw.dev/session/redirect/index.html (200)

index.html uses resource https://mac9416.com/demos/style.css (I just needed an external domain name).

I want to instruct the browser to connect to mac9416.com in the 302 rather than the 200.

Some browsers support resource hint headers. Here are some examples:

EXAMPLE 5

Link: https://widget.com; rel=dns-prefetch
Link: https://example.com; rel=preconnect
Link: https://example.com/next-page.html; rel=prerender;
Link: https://example.com/logo-hires.jpg; rel=prefetch; as=image;

Dev tools shows the Link header in the initial request:

I see the connection to mac9416.com established after the 200, immediately before the resource is downloaded.

I expected to see the connection established immediately after the 302, or simply missing from the timeline.

I tested using Chrome 73. The WebPageTest waterfall looks almost identical.

Note: I'm interested in server-push solutions, but for now the site in question runs HTTP1.1.

Am I attempting something that isn't even supported? Must resource hint headers be served on non-redirect responses only?

The "Anonymizing redirect" section of the resource hint working draft leads me to believe it's meant to help in exactly my type of situation. But maybe I'm misreading.

Many sites rely on redirect services for analytics, malware protection, and to anonymize the referrer before sending the user to the final destination. Because the destination is known ahead of time, a preconnect hint can be used to initiate the connection handshake with the destination origin (without revealing any private information) in parallel with the processing of the redirect - this masks the redirect latency and reduces navigation time to final destination.