transactionIsBalanced method
just return true or false if the transaction is balanced.
Implementation
Result<bool, String> transactionIsBalanced({
required BlockchainCache cache,
Coin fee = 0,
}) {
final result = sumCurrencyIO(cache: cache, fee: fee);
if (result.isErr()) return Err(result.unwrapErr());
final sums = result.unwrap();
final isAllZeros = sums.values.every((sum) => sum == coinZero);
return Ok(isAllZeros);
}