Re: Using preload for "async" CSS by changing `rel` trick

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>> We use the fact that a resource has been downloaded to reveal content
>> that depends on the JS/CSS that we are fetching. So if rel=preload told use
>> a.css is available we'll insert HTML that uses a.css into the DOM. Even a
>> single frame of the browser doing something like parsing the file would
>> create a disruptive user experience.
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> Right, I see. I think that's a great use case to raise against HTML spec
> and see what the guidance is there — this is not preload specific, same
> applies for resources coming from HTTP cache, serviceworker, etc.
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Is the correct formulation of the question "does the presence of a resource
in the fetch group's response cache [which is what the preload spec says it
adds the stylesheet to] guarantee that inserting a <link> with an href to
that resource will synchronously apply to the DOM"

-b