code: func serializeWriteRow(curBlockFileNum, curFileOffset uint32) []byte {
  	var serializedRow [12]byte
  	byteOrder.PutUint32(serializedRow[0:4], curBlockFileNum)
  	byteOrder.PutUint32(serializedRow[4:8], curFileOffset)
  	checksum := crc32.Checksum(serializedRow[:8], castagnoli)
  	byteOrder.PutUint32(serializedRow[8:12], checksum)
  	return serializedRow[:]
  }
docs: // The serialized write cursor location format is:
  //
  //  [0:4]  Block file (4 bytes)
  //  [4:8]  File offset (4 bytes)
  //  [8:12] Castagnoli CRC-32 checksum (4 bytes)
  // serializeWriteRow serialize the current block file and offset where new
  // will be written into a format suitable for storage into the metadata.