public ArrayDeque<Integer> getBucket(int index) {
    return buckets[index];
  }
* Index buckets affiliated to a page collection. Indexes are sort into buckets according to spare
space of its corresponding page instance.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/schemafile/pagemgr/PageIndexSortBuckets.java