DirectBoot sample fails with java.lang.UnsatisfiedLinkError

[mungojam]

Sample link

https://developer.xamarin.com/samples/monodroid/android-n/DirectBoot/

Issue description

The DirectBoot sample fails to sound an alarm as expected and instead throws this error in the log:

08-18 22:54:33.644 2722 2722 E AndroidRuntime: FATAL EXCEPTION: main
08-18 22:54:33.644 2722 2722 E AndroidRuntime: Process: com.xamarin.directboot, PID: 2722
08-18 22:54:33.644 2722 2722 E AndroidRuntime: java.lang.UnsatisfiedLinkError: No implementation found for void mono.android.Runtime.register(java.lang.String, java.lang.Class, java.lang.String) (tried Java_mono_android_Runtime_register and Java_mono_android_Runtime_register__Ljava_lang_String_2Ljava_lang_Class_2Ljava_lang_String_2)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at mono.android.Runtime.register(Native Method)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at md511db93b05d0fbee144be45ad6fb54d50.BootBroadcastReceiver.(BootBroadcastReceiver.java:15)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at java.lang.Class.newInstance(Native Method)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at android.app.ActivityThread.handleReceiver(ActivityThread.java:3671)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at android.app.ActivityThread.-wrap18(Unknown Source:0)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1979)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:108)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at android.os.Looper.loop(Looper.java:166)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:7425)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at java.lang.reflect.Method.invoke(Native Method)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
08-18 22:54:33.644 2722 2722 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)

Steps to reproduce the issue

1. Download and build the sample
2. Deploy to device
3. Set an alarm for a few minutes time
4. Reboot and wait for alarm time
5. Nothing happens
6. Check adb logcat and above error is there

What's the expected result?

Alarm will sound at expected time

What's the actual result?

It doesn't and errors instead

Additional details / screenshot (Optional)

This is on an Huawei Honor 9 (STF-L09) with Oreo 8.0.0

I've also hit this same error with my own attempts to implement a Xamarin direct boot app, so I wonder if it is a bug with Xamarin.Android itself