private TsBlock buildTsBlock() {
    try {
      TsBlockBuilder builder = new TsBlockBuilder(Collections.singletonList(dataType));
      writeValidValuesIntoTsBlock(builder);
      return builder.build();
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }
ReadOnlyMemChunk is a snapshot of the working MemTable and flushing memtable in the memory used
for querying.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/memtable/ReadOnlyMemChunk.java