io.reactivex.rxjava3.exceptions.UndeliverableException: The exception could not be delivered to the consumer because it has already canceled/disposed the flow or the exception has nowhere to go to begin with. Further reading: https://github.com/ReactiveX/RxJava/wiki/What's-different-in-2.0#error-handling | java.util.ConcurrentModificationException at io.reactivex.rxjava3.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:367) at io.reactivex.rxjava3.internal.schedulers.ScheduledDirectTask.call(ScheduledDirectTask.java:48) at io.reactivex.rxjava3.internal.schedulers.ScheduledDirectTask.call(ScheduledDirectTask.java:28) at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) at java.base/java.lang.Thread.run(Thread.java:832)Caused by: java.util.ConcurrentModificationException: null at java.base/java.util.HashMap$HashIterator.nextNode(HashMap.java:1584) at java.base/java.util.HashMap$KeyIterator.next(HashMap.java:1607) at com.google.common.collect.AbstractMapBasedMultimap$WrappedCollection$WrappedIterator.next(AbstractMapBasedMultimap.java:463) at com.google.common.collect.AbstractMapBasedMultimap.replaceValues(AbstractMapBasedMultimap.java:234) at com.google.common.collect.AbstractSetMultimap.replaceValues(AbstractSetMultimap.java:112) at com.google.common.collect.HashMultimap.replaceValues(HashMultimap.java:46) at org.drasyl.peer.PeersManager.handlePeerStateTransition(PeersManager.java:217) at org.drasyl.peer.PeersManager.setPeerInformation(PeersManager.java:237) at org.drasyl.peer.connection.localhost.LocalHostDiscovery.scan(LocalHostDiscovery.java:206) at org.drasyl.peer.connection.localhost.LocalHostDiscovery.open(LocalHostDiscovery.java:130) at org.drasyl.DrasylNode.lambda$start$4(DrasylNode.java:438) at io.reactivex.rxjava3.internal.schedulers.ScheduledDirectTask.call(ScheduledDirectTask.java:41) ... 5 common frames omitted