public static Object assertThreadIdToSequenceIdMapHasEntryId() {
    Map map = pool.getThreadIdToSequenceIdMap();
    assertNotNull(map);
    // The map size can now be 1 or 2 because of the server thread putting
    // the marker in the queue. If it is 2, the first entry is the server
    // thread; the second is the client thread. If it is 1, the entry is the
    // client thread. The size changes because of the map.clear call below.
    assertTrue(map.size() != 0);

    // Set the entry to the last entry
    Map.Entry entry = null;
    for (final Object o : map.entrySet()) {
      entry = (Map.Entry) o;
    }

    ThreadIdentifier tid = (ThreadIdentifier) entry.getKey();
    SequenceIdAndExpirationObject seo = (SequenceIdAndExpirationObject) entry.getValue();
    long sequenceId = seo.getSequenceId();
    EventID evId = new EventID(tid.getMembershipID(), tid.getThreadID(), sequenceId);
    synchronized (map) {
      map.clear();
    }
    return evId;
  }
function to assert that the ThreadIdtoSequence id Map is not Null and has only one entry *
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ha/HAEventIdPropagationDistributedTest.java