Prefetch on hover works in Chrome, not Firefox

[david-crespo]

This is reproducible locally, so that's nice.

Firefox

Red line is the prefetch request, which is aborted. Third from bottom is when I click, and the data is fetched again, taking the full 160ms instead of using the prefetched data.

Especially confusing is the fact that we seem to have a response for the aborted one, but it looks like malformed JSON. The working request on click has the same format and seems to work fine, so I'm guessing this is Remix's special format for responses with deferred data. I do think @augustuswm might be right in guessing that something funny might be going on with the deferred data. It should be easy to test this with the defer bit commented out.

Chrome

First request is when I hover over an RFD, second is when I click. The data are retrieved from a special browser cache for prefetches, and this is nearly instant.