public List<Object> getKeys(String regionName) {
    final Region<?, ?> r = cache.getRegion(SEPARATOR + regionName);
    return new ArrayList<>(r.keySet());
  }
To be used only for ParallelGatewaySender.

@param senderId Id of the ParallelGatewaySender
geode-wan/src/distributedTest/java/org/apache/geode/internal/cache/wan/WANTestBase.java