Fix Accept + Add Except

Author: mythz

src/ServiceStack.Text/HttpRequestConfig.cs

@@ -12,6 +12,7 @@ public class HttpRequestConfig
     public string? UserAgent { get; set; } 
     public string? ContentType { get; set; }
     public string? Referer { get; set; }
+    public string? Expect { get; set; } 
     public NameValue? Authorization { get; set; }
     public LongRange? Range { get; set; }
     public List<NameValue> Headers { get; set; } = new();

src/ServiceStack.Text/HttpUtils.HttpClient.cs

@@ -1108,6 +1108,8 @@ public static HttpRequestMessage With(this HttpRequestMessage httpReq, Action<Ht
                 new AuthenticationHeaderValue(config.Authorization.Name, config.Authorization.Value);
         if (config.Range != null)
             httpReq.Headers.Range = new RangeHeaderValue(config.Range.From, config.Range.To);
+        if (config.Expect != null)
+            httpReq.Headers.Expect.Add(new(config.Expect));
 
         foreach (var entry in headers)
         {

src/ServiceStack.Text/HttpUtils.WebRequest.cs

@@ -1118,7 +1118,7 @@ public static HttpWebRequest With(this HttpWebRequest httpReq, Action<HttpReques
         configure(config);
 
         if (config.Accept != null)
-            httpReq.Headers.Add(HttpHeaders.Accept, config.Accept);
+            httpReq.Accept = config.Accept;
 
         if (config.UserAgent != null)
             httpReq.UserAgent = config.UserAgent;
@@ -1136,6 +1136,9 @@ public static HttpWebRequest With(this HttpWebRequest httpReq, Action<HttpReques
         if (config.Range != null)
             httpReq.SetRange(config.Range.From, config.Range.To);
 
+        if (config.Expect != null)
+            httpReq.Expect = config.Expect;
+
         foreach (var entry in config.Headers)
         {
             httpReq.Headers[entry.Name] = entry.Value;