private void processModifiedChunk(Chunk chunk) throws IOException {
    if (cachedChunk != null) {
      // if there is a cached chunk, deserialize it and write it to ChunkWriter
      writeCachedChunkIntoChunkWriter();
    }
    summary.increaseDeserializedChunkNum(1);
    // write this chunk to ChunkWriter
    writeChunkIntoChunkWriter(chunk);
    flushChunkWriterIfLargeEnough();
  }
This function execute the compaction of a single time series. Notice, the result of single
series compaction may contain more than one chunk.

@throws IOException if io errors occurred
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/compaction/execute/utils/executor/readchunk/SingleSeriesCompactionExecutor.java