11:43:20,272 PM [testsystem-pekko.actor.default-dispatcher-4] [INFO] Slf4jLogger - Slf4jLogger started
11:43:20,625 PM [testsystem-pekko.actor.default-dispatcher-4] [INFO] RepointableActorRef -  pekkoDeadLetter Message [java.lang.String] from Actor[pekko://testsystem/system/testActor-51#-1487759349] to Actor[pekko://testsystem/user/pingpongactor#-856850202] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[pekko://testsystem/user/pingpongactor#-856850202] may have terminated unexpectedly. This logging can be turned off or adjusted with configuration settings 'pekko.log-dead-letters' and 'pekko.log-dead-letters-during-shutdown'.
11:43:20,630 PM [testsystem-pekko.actor.default-dispatcher-8] [INFO] CoordinatedShutdown - Running CoordinatedShutdown with reason [ActorSystemTerminateReason]