Current implementation will strip headers with same key

[quangIO]

The Headers struct uses HashMap to hold key-value pairs. However, headers can have same keys. For conforming headers, we can join them into one string, but it is not the case for all headers, especially when their values can contain comma(s). Thus, sxg-rs should use a multi-map (e.g. HeaderMap in http).

I can help replacing the current implementation if you think it makes sense.

[twifkak]

Good catch. Note that the signed exchanges spec disallows duplicate headers, so the processor must join them with a comma before signing.

The HTTP spec considers this operation safe except for Set-Cookie but that's OK since the SXG spec disallows Set-Cookie anyway. (sxg-rs either strips it or cancels signing, depending on configuration.)

[quangIO]

Thank you for the clarification! I just open a small pull request that should support RFC-conforming headers.