private Set<Integer> getBucketList(String regionName) {
    PartitionedRegion region = (PartitionedRegion) getCache().getRegion(regionName);
    return new TreeSet<>(region.getDataStore().getAllLocalBucketIds());
  }
NOTE: do not replace createPartitionedRegionRunnable with lambda
because ResourceObserverAdapter is NOT serializable
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/control/RebalanceOperationDistributedTest.java