nsurlsessionuploadtask

I am trying to upload some 100 images to S3 in the background with AFURLSessionManager in small batches of 10 like what is being done here- Manage the number of active tasks in a background NSURLSession I am using a shared NSURLSession and adding tasks according more tasks to this when some tasks are completed. Average size of each file is about 1.6 MB and the number of tasks that are guaranteed to run per a task queue is 5 Here is my method for adding the tasks: (also available as an easier-to-read gist ) - (void) addTasksToSessionWithTaskObject:(Task*)taskObject

I am using NSURLSession for background image uploading. And according to uploaded image my server gives me response and I do change in my app accordingly. But I can't get my server response when my app uploading image in background because there is no completion block. Is there way to get response without using completion block in NSURLUploadTask ? Here is my code : self.uploadTask = [self.session uploadTaskWithRequest:request fromData:body completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { NSString *returnString = [[NSString alloc] initWithData:data encoding