code: func StorageTrieID(state *TrieID, addrHash, root common.Hash) *TrieID {
  	return &TrieID{
  		BlockHash:   state.BlockHash,
  		BlockNumber: state.BlockNumber,
  		AccKey:      addrHash[:],
  		Root:        root,
  	}
  }
docs: // StorageTrieID returns a TrieID for a contract storage trie at a given account
  // of a given state trie. It also requires the root hash of the trie for
  // checking Merkle proofs.