public Optional<Wei> accountBalance(final Address address, final Hash blockHash) {
    return fromAccount(address, blockHash, Account::getBalance, Wei.ZERO);
  }
Returns the balance of the given account at a specific block hash.

@param address The address of the account being queried.
@param blockHash The block hash being queried.
@return The balance of the account in Wei.
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/query/BlockchainQueries.java