For future reference: https://android.googlesource.com/platform/frameworks/base/+/dafed3d00818713b60ec09cfff482487a3405202

Pre 8.1 didn't have this fix, and so unregisterNetworkCallback would only unregister the most recent request and "leak" prior requests. An app can only have up to 100 ongoing requests at a time, otherwise it'll throw an exception. Notably, WebRTC also registers a callback in NetworkMonitorAutoDetect, so the exception would crash the app.