ResponseData.Headers can't deal with multiple headers with same name

Description

The Headers field of the ResponseData is a map of header name to header value. This assumes that every header type can be set only once, but this is assumption is not correct. E.g. the Set-Cookie may be listen multiple times.

In System.Net.Http this is solved by using a Map which maps the header name to a list of values.

Complete minimal example reproducing the issue

When intercepting the http request, it is not possible to set multiple cookies:

E.g.

        private async Task InterceptAsync(RequestEventArgs args)
        {
            var responseData = new ResponseData
            {
                Body = "{\"success\": true}",
                ContentType = "application/json; charset=utf-8",
                Headers = new Dictionary<string, object>(),
                Status = HttpStatusCode.OK
            };
            
            responseData.Headers.Add("Set-Cookie", "session=xyz; path=/; samesite=none");
            responseData.Headers.Add("Set-Cookie", "addition=abc; path=/; samesite=none");

            await args.Request.RespondAsync(responseData);
        }

Expected behavior:

It should be possible to set headers multiple times with same name.

Actual behavior:

Only one value per header name can be added.

Versions

• PuppeteerSharp: 2.0.4
• .NET: .NET Core 3.1.3

[kblok]

If you can make it work without breaking any test, go for it!

[L6Echo]

The headers property is an Array of HeaderEntries. So it should be possible to set multiple headers with the same name. Except the protocol checks for uniqueness of header names. But I wouldn’t expect this. Because it is a legit case.

Yes, currently i did a workaround with SetCookieAsync. But this bypasses the cookie handling of chrome and this may distort the test result. Additional the cookie header must be parsed manually which may also behave different than the chrome cookie handling itself.