Represents an input referencing an output.
### from(id, index): [UtxoInput](#utxoinput)
Create a new `UtxoInput`
| Parameter | Type | Description |
| --------------- | -------- | -------- |
| id | [TransactionId](#transactionid) | The ouput Id |
| index | int | The output Index |
### transactionId(): [TransactionId](#transactionid)
Returns the `TransactionId` of the Output.
### index(): int
Returns the index of the Output.