MS-4811 Fix: Crash with MAR.stop on BGThread
MS-4811 Fix: Crash with MAR.stop on BGThread

Squashed commit of the following:

commit 8f4e220c63b19a4eaf1ece608b2fdf796aed6370
Author: Abhas Vohra <avohra@appnexus.com>
Date:   Mon Sep 27 19:02:07 2021 +0530

    Fix: MAR.stop BGThreading crash

appnexus/mobile-sdk-android,appnexus/mobile-sdk-android,appnexus/mobile-sdk-android,appnexus/mobile-sdk-android,appnexus/mobile-sdk-android