As AsParallel when filtering

MediaBrowser.Api/UserLibrary/ItemsService.cs

@@ -181,6 +181,8 @@ namespace MediaBrowser.Api.UserLibrary
 
             var items = GetItemsToSerialize(request, user);
 
+            items = items.AsParallel();
+
             // Apply filters
             // Run them starting with the ones that are likely to reduce the list the most
             foreach (var filter in GetFilters(request).OrderByDescending(f => (int)f))
@@ -190,6 +192,8 @@ namespace MediaBrowser.Api.UserLibrary
 
             items = ApplyAdditionalFilters(request, items);
 
+            items = items.AsEnumerable();
+
             items = ApplySearchTerm(request, items);
 
             items = ApplySortOrder(request, items, user);