Integer getNumOfChunksReturnedToPool(Set<Integer> chunksId) {
    int i = 0;
    for (Integer id : chunksId) {
      if (chunkCreator.isChunkInPool(id)) {
        i++;
      }
    }
    return i;
  }
Get the current chunk, or, if there is no current chunk, allocate a new one from the JVM.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreLABImpl.java