HttpHeaders don't always preserve order

gistfile1.cs

        [Fact]
        public void DoesNotPreserveHttpHeaderValueOrderOrCase()
        {
            var response = new HttpResponseMessage();
            string input = "Private, max-age=60, s-maxage=60";
            
            response.Headers.TryAddWithoutValidation("Cache-Control", input);
            var header = response.Headers.First();
            var output = string.Join(",", header.Value);
            Assert.NotEqual(input,output);

        }

        [Fact]
        public void PreserveHttpHeaderValueOrderInAcceptLang()
        {
            var response = new HttpResponseMessage();
            string input = "fr-ca, en, fr, en-ca";

            response.Headers.TryAddWithoutValidation("Accept-Language", input);
            var header = response.Headers.First();
            var output = string.Join(",", header.Value);
            Assert.Equal(input, output);

        }