BlockingQueue<Chunk> getPooledChunks() {
    BlockingQueue<Chunk> pooledChunks = new LinkedBlockingQueue<>();
    for (Integer id : this.chunks) {
      Chunk chunk = chunkCreator.getChunk(id);
      if (chunk != null && chunk.isFromPool()) {
        pooledChunks.add(chunk);
      }
    }
    return pooledChunks;
  }
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