11:42:53,234 PM [testsystem-pekko.actor.default-dispatcher-5] [INFO] Slf4jLogger - Slf4jLogger started
11:42:53,538 PM [testsystem-pekko.actor.default-dispatcher-6] [INFO] RepointableActorRef -  pekkoDeadLetter Message [java.lang.String] from Actor[pekko://testsystem/system/testActor-51#-1667258591] to Actor[pekko://testsystem/user/pingpongactor#1872288229] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[pekko://testsystem/user/pingpongactor#1872288229] 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'.
11:42:53,539 PM [testsystem-pekko.actor.default-dispatcher-6] [INFO] CoordinatedShutdown - Running CoordinatedShutdown with reason [ActorSystemTerminateReason]