@SuppressWarnings("rawtypes")
    @Override
    public Set<VersionSource> clearEntries(final RegionVersionVector rvv) {
      final AtomicReference<Set<VersionSource>> result = new AtomicReference<>();
      OffHeapClearRequired.doWithOffHeapClear(() -> result.set(super.clearEntries(rvv)));
      return result.get();
    }
shutdown this thread and the caller thread will join this thread
geode-core/src/main/java/org/apache/geode/internal/cache/wan/serial/SerialGatewaySenderQueue.java