We've been seeing a lot of socket timeouts on REST requests under
certain conditions. The issue seems to be a problem with the OkHttp
client. Through testing, I've seen that resetting the receiver and
retrying again seems to resolve most issues.
Due to an Android P bug, we basically need to stop calling
startService() in onResume()/onPause(). That means I had to turn
MessageRetrieval service into a singlton instead of a service. I also
moved the offending KeyCachingService calls into static methods that
didn't have to start the service.