[fetch] Can headers ordering be lessened? (#189)

Headers currently store header name value pairs as an ordered list
If the ordering is lessened to keep only ordering between headers that have a same name, a more efficient structure could be used (ordered multimap)

In non service-worker cases at least, there seems to be little value to keep that strong ordering

This is a follow-up of discussion from https://githubcom/whatwg/fetch/issues/154

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Reply to this email directly or view it on GitHub:
https://github.com/whatwg/fetch/issues/189