private void handleUnSuccessfulBatchDispatch(List<?> events) {
    final GatewaySenderStats statistics = sender.getStatistics();
    statistics.incBatchesRedistributed();
    // Set posDup flag on each event in the batch
    notifyPossibleDuplicate(UNSUCCESSFULLY_DISPATCHED, events);
  }
Mark all PDX types as requiring dispatch so that they will be sent over the connection again.
geode-core/src/main/java/org/apache/geode/internal/cache/wan/AbstractGatewaySenderEventProcessor.java