System.Net.Http.Headers.HttpContentHeaders.CreateInvalidHeaders C# (CSharp) Method

        private static HashSet<string> CreateInvalidHeaders()
        {
            var invalidHeaders = new HashSet<string>(StringComparer.OrdinalIgnoreCase);

            HttpRequestHeaders.AddKnownHeaders(invalidHeaders);
            HttpResponseHeaders.AddKnownHeaders(invalidHeaders);
            HttpGeneralHeaders.AddKnownHeaders(invalidHeaders);

            return invalidHeaders;
        }