public static void dumpPoolIdentifiers() throws Exception {
    // duplicate events were received, so let's look at the thread identifiers we have
    PoolImpl pool = (PoolImpl) PoolManager.find("ClientServerMiscDUnitTestPool");

    Map seqMap = pool.getThreadIdToSequenceIdMap();
    for (Object o : seqMap.keySet()) {
      ThreadIdentifier tid = (ThreadIdentifier) o;
      byte[] memberBytes = tid.getMembershipID();
      dumpMemberId(tid, memberBytes);
    }
  }
bug 35380: Cycling a DistributedSystem with an initialized pool causes interest registration
NPE

Test Scenario:

Create a DistributedSystem (DS1). Create a pool, initialize (creates a proxy with DS1 memberid)
Disconnect DS1. Create a DistributedSystem (DS2). Create a Region with pool, it attempts to
register interest using DS2 memberid, gets NPE.
geode-dunit/src/main/java/org/apache/geode/internal/cache/tier/sockets/ClientServerMiscDUnitTestBase.java