@Override
  public Set<Object> getKeys() {
    synchronized (LOCK) {
      return Collections.synchronizedSet(new HashSet<>(cqResultKeys.keySet()));
    }
  }
For Test use only.

@return CQ Results Cache.
geode-cq/src/main/java/org/apache/geode/cache/query/cq/internal/ServerCQResultsCacheReplicateRegionImpl.java