add the extended exception

ClientExtApiException.cs

@@ -0,0 +1,33 @@
+#pragma warning disable 1591
+
+
+using System;
+using NAMESPACEPLACEHOLDER.Model;
+using Newtonsoft.Json;
+
+
+namespace NAMESPACEPLACEHOLDER.Client {
+    class ExtApiException: ApiException {
+        public int ErrorCode { get; }
+        public int ServiceErrorCode { get; }
+        public String OffensiveData { get; }
+
+        public ExtApiException(ErrorResultObject ero): base(ero.errorCode, ero.errorMessage, ero) {
+            ErrorCode = ero.errorCode;
+            ServiceErrorCode = ero.serviceErrorCode;
+            OffensiveData = ero.offensiveData;
+        }
+
+        public static ExceptionFactory ExtExceptionFactory = (methodName, response) => {
+            var status = (int) response.StatusCode;
+            if (status >= 400) {
+                var ero = JsonConvert.DeserializeObject<ErrorResultObject>(response.RawContent);
+                return new ExtApiException(ero);
+            }
+            return null;
+        };
+    }
+}
+
+
+#pragma warning restore 1591