12:20:53,321 PM [testsystem-pekko.actor.default-dispatcher-5] [INFO] Slf4jLogger - Slf4jLogger started
12:20:53,655 PM [testsystem-pekko.actor.default-dispatcher-7] [INFO] RepointableActorRef -  pekkoDeadLetter Message [java.lang.String] from Actor[pekko://testsystem/system/testActor-13#427601809] to Actor[pekko://testsystem/user/pingpongactor#-1397693580] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[pekko://testsystem/user/pingpongactor#-1397693580] 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'.
12:20:53,659 PM [testsystem-pekko.actor.default-dispatcher-5] [INFO] CoordinatedShutdown - Running CoordinatedShutdown with reason [ActorSystemTerminateReason]