Applying contribution from Evgeniya Polyakova.

Thanks to Gustavo Rubinsky for a similar patch.

Author: moonpyk

CONTRIBUTORS.txt

@@ -0,0 +1,2 @@
+Evgeniya Polyakova <epolyakova@knoema.com> : Fixed issue #2584
+Gustavo Rubinsky <grubinsky@yellowspot.com.ar> : Similar fix for issue #2584

DevTrends.MvcDonutCaching/DonutOutputCacheAttribute.cs

@@ -100,8 +100,10 @@ public override void OnActionExecuting(ActionExecutingContext filterContext)
 
         public override void OnResultExecuted(ResultExecutedContext filterContext)
         {
-			if(_cacheSettings == null)
-				return;
+            if (_cacheSettings == null)
+            {
+                return;
+            }
 
             ExecuteCallback(filterContext, false);