ParallelGatewaySenderQueueMetaRegion newMetataRegion(InternalCache cache, final String prQName,
        final RegionAttributes ra, AbstractGatewaySender sender) {
      ParallelGatewaySenderQueueMetaRegion meta =
          new ParallelGatewaySenderQueueMetaRegion(prQName, ra, null, cache, sender,
              sender.getStatisticsClock());
      return meta;
    }
shutdown this thread and the caller thread will join this thread
geode-core/src/main/java/org/apache/geode/internal/cache/wan/parallel/ParallelGatewaySenderQueue.java