NSURLSessionConfiguration

Called on a session configuration before it’s used to instantiate an NSURLSession instance.

This should ONLY be called if the configuration is NOT the defaultSessionConfiguration.

Swift:

   let configuration = NSURLSessionConfiguration.ephemeralSessionConfiguration()
   configuration.addCaffeine()
   let session = NSURLSession(configuration: configuration)
   let request = NSMutableURLRequest(URL: NSURL(string: "http://google.com")!)
   session.dataTaskWithRequest(request) { (data, res, err) -> Void in
       print("I used Caffeine to get here")
   }.resume()

Objective-C:

   NSURLSessionConfiguration *config = [NSURLSessionConfiguration ephemeralSessionConfiguration];
   [config addCaffeine];
   NSURLSession *session = [NSURLSession sessionWithConfiguration:config];
   [session dataTaskWithURL:[NSURL URLWithString:@"http://google.com"] completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
       NSLog(@"I used Caffeine to get here");
   }];