public Map<Integer, Boolean> getBuckets() {
    return buckets;
  }
tracks bucketIds of transactional operations so as to distinguish between
TransactionDataNotColocated and TransactionDataRebalanced exceptions. Map rather than set, as a
HashSet is backed by a HashMap. (avoids one "new" call).
geode-core/src/main/java/org/apache/geode/internal/cache/tx/PartitionedTXRegionStub.java