persistent audible alerts

A very basic feature is missing in the Android app: persistent audible alert. I can be asleep when the alarm comes, and then I want the notification to work just as an alarm clock, it continues to ring for several minutes or until I manually acknowledges it.

I know about "priority: 2", but that is not really the same thing. A single sound every 30 second is not a wakeup alarm. An alarm to wake me up should be a persistent audible alert, just as my alarm clock in the morning.

As a workaround I can select the longest sound you have as default sound and use priority: 2, but it would be much better if you added persistent alarm on the client side as an option for us that sleep hard.