Async functions do not return a Task type. If the parameter is empty, an exception will be returned. System.NullReferenceException

framework/test/Volo.Abp.Http.Client.Tests/Volo/Abp/Http/DynamicProxying/TestObjectToFormData.cs

@@ -15,7 +15,7 @@ public class TestObjectToFormData : IObjectToFormData<List<GetParamsNameValue>>,
     {
         if (values.IsNullOrEmpty())
         {
-            return null;
+            return Task.FromResult<List<KeyValuePair<string, HttpContent>>>(null);
         }
 
         var formDataContents = new List<KeyValuePair<string, HttpContent>>();