KeepAlive.m

- (void)keepAliveHandler:(UIBackgroundTaskIdentifier)bgIdentifier {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
        NSLog(@"Runnin' in the background!");

        for (int i = 49; i >= 1; --i) {
            NSLog(@"Okay, %i more!", i);
            [NSThread sleepForTimeInterval:6];
        }

        NSLog(@"Phew! Made it through!");
        [[UIApplication sharedApplication] endBackgroundTask:bgIdentifier];
    });
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    
    [application setKeepAliveTimeout:600
                             handler:^{
                                 UIBackgroundTaskIdentifier bgIdentifier = [application beginBackgroundTaskWithExpirationHandler:^{
                                     NSLog(@"Runnin' out of time, cap'n!");
                                 }];
                                 [self keepAliveHandler:bgIdentifier];
                             }];
    // ....
}