AFNetworking/AFNetworkActivityLogger — pull request #19 by IshchenkoAndriy (2014-10-13 12:16:17+00:00)
Title: Fixed receiving of serialization errors for NSURLSessionTasks.

According to Apple documentation method 'error' of NSURLSessionTask returns only client side errors.
It seems like response serialization errors for NSURLSessionTask are included in the userInfo dictionary.