[Modify] Replace it

websocket-sharp/Net/WebHeaderCollection.cs

@@ -1846,17 +1846,9 @@ namespace WebSocketSharp.Net
       checkRestricted (name);
       checkAllowed (name);
 
-      base.Set (name, value);
-
-      if (_state != HttpHeaderType.Unspecified)
-        return;
-
       var headerType = getHeaderType (name);
 
-      if (headerType == HttpHeaderType.Unspecified)
+      set (name, value, headerType);
-        return;
-
-      _state = headerType;
     }
 
     /// <summary>