code: func NewCompressingStoredFieldsFormat(formatName, segmentSuffix string,
  	compressionMode CompressionMode, chunkSize int) *CompressingStoredFieldsFormat {
  	assert2(chunkSize >= 1, "chunkSize must be >= 1")
  	return &CompressingStoredFieldsFormat{
  		formatName:      formatName,
  		segmentSuffix:   segmentSuffix,
  		compressionMode: compressionMode,
  		chunkSize:       chunkSize,
  	}
  }
docs: /*
  Create a new CompressingStoredFieldsFormat
  
  formatName is the name of the format. This name will be used in the
  file formats to perform CheckHeader().
  
  segmentSuffix is the segment suffix. This suffix is added to the result
   file name only if it's not te empty string.
  
   The compressionMode parameter allows you to choose between compresison
   algorithms that have various compression and decompression speeds so
   that you can pick the one that best fits your indexing and searching
   throughput. You should never instantiate two CoompressingStoredFieldsFormats
   that have the same name but different CompressionModes.
  
   chunkSize is the minimum byte size of a chunk of documents. A value
   of 1 can make sense if there is redundancy across fields. In that
   case, both performance and compression ratio should be better than
   with Lucene40StoredFieldsFormat with compressed fields.
  
   Higher values of chunkSize should improve the compresison ratio but
   will require more memery at indexing time and might make document
   loading a little slower (depending on the size of our OS cache compared
   to the size of your index).
  */