public Set getBucketKeys(int bucketNum) {
    return getBucketKeys(bucketNum, false);
  }
Fetch the keys for the given bucket identifier, if the bucket is local or remote.

@return A set of keys from bucketNum or {@link Collections#EMPTY_SET}if no keys can be found.
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionedRegion.java