code: func (c *ChtIndexerBackend) Process(ctx context.Context, header *types.Header) error {
  	hash, num := header.Hash(), header.Number.Uint64()
  	c.lastHash = hash
  
  	td := rawdb.ReadTd(c.diskdb, hash, num)
  	if td == nil {
  		panic(nil)
  	}
  	var encNumber [8]byte
  	binary.BigEndian.PutUint64(encNumber[:], num)
  	data, _ := rlp.EncodeToBytes(ChtNode{hash, td})
  	c.trie.Update(encNumber[:], data)
  	return nil
  }
docs: // Process implements core.ChainIndexerBackend