AFNetworking 2.0 add headers to GET request

Here’s an example using AFNetworking 2.0

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
manager.responseSerializer = [AFJSONResponseSerializer serializer];
manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager.requestSerializer setValue:@"calvinAndHobbesRock" forHTTPHeaderField:@"X-I do what I want"];

[manager GET:@"http://localhost:3000" parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSLog(@"JSON: %@", responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error);
}];

The key are the following 2 lines:

manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager.requestSerializer setValue:@"calvinAndHobbessRock" forHTTPHeaderField:@"X-I-do-what-I-want"];