使用beginBackgroundTaskWithExpirationHandler时，iOS不会在时间到期后终止应用程序

Question

我有一个开关，我在我的iPhone应用程序上打开，当我打开它并将其放在后台时，我在后台运行应用程序。

- (IBAction)doBackgroundEnableSwitch:(id)sender {
    UISwitch *mySwitch = sender;
    if (mySwitch.on) {
        self.myBackgroundTaskID = [[UIApplication sharedApplication]beginBackgroundTaskWithExpirationHandler:^{
            NSLog(@"WE RAN OUT OF TIME!");
            //abort(); //Crash if we get here. (shouldn't be necessary because we ran out of time. I am purposely not 
        }];
        NSLog(@"MyBackgroundTaskID = %lu", self.myBackgroundTaskID);
    } else {
        [[UIApplication sharedApplication]endBackgroundTask:self.myBackgroundTaskID];
    }
}

当应用程序在后台运行时，使用NSLog我正在计算剩余时间。

- (void)displayApplicationState {
    switch ([UIApplication sharedApplication].applicationState) {
        case UIApplicationStateActive:
            NSLog(@"UIApplicationStateActive");
            break;
        case UIApplicationStateBackground:
            NSLog(@"UIApplicationStateBackground");
            break;
        case UIApplicationStateInactive:
            NSLog(@"UIApplicationStateInactive");
            break;
        default:
            break;
    }
    NSLog(@"timeRemaining: %f", [UIApplication sharedApplication].backgroundTimeRemaining);
}

然而，当该计数达到0.00时，我的应用程序不会崩溃。 Apple文档称它应该崩溃。发生了什么事？

这是我的完整ViewController.h https://gist.github.com/RommelTJ/38560b273d4501f81439