code: func (c *ChainIndexer) setSectionHead(section uint64, hash common.Hash) {
  	var data [8]byte
  	binary.BigEndian.PutUint64(data[:], section)
  
  	c.indexDb.Put(append([]byte("shead"), data[:]...), hash.Bytes())
  }
docs: // setSectionHead writes the last block hash of a processed section to the index
  // database.