Icon LinkTransaction policies

Transaction policies are defined as follows:

pub struct TxPolicies {
    gas_price: Option<u64>,
    witness_limit: Option<u64>,
    maturity: Option<u64>,
    max_fee: Option<u64>,
    script_gas_limit: Option<u64>,
}

Where:

1. Gas Price - Maximum gas price for transaction.
2. Witness Limit - The maximum amount of witness data allowed for the transaction.
3. Maturity - Block until which the transaction cannot be included.
4. Max Fee - The maximum fee payable by this transaction.
5. Script Gas Limit - The maximum amount of gas the transaction may consume for executing its script code.

When the Script Gas Limit is not set, the Rust SDK will estimate the consumed gas in the background and set it as the limit. Similarly, if no Gas Price is defined, the Rust SDK defaults to the network's minimum gas price.

If the Witness Limit is not set, the SDK will set it to the size of all witnesses and signatures defined in the transaction builder.

You can configure these parameters by creating an instance of TxPolicies and passing it to a chain method called with_tx_policies:

let contract_methods = MyContract::new(contract_id.clone(), wallet.clone()).methods();
 
let tx_policies = TxPolicies::default()
    .with_gas_price(1)
    .with_script_gas_limit(1_000_000)
    .with_maturity(0);
 
let response = contract_methods
    .initialize_counter(42) // Our contract method
    .with_tx_policies(tx_policies) // Chain the tx policies
    .call() // Perform the contract call
    .await?; // This is an async call, `.await` it.

You can also use TxPolicies::default() to use the default values.

This way:

let response = contract_methods
    .initialize_counter(42)
    .with_tx_policies(TxPolicies::default())
    .call()
    .await?;

As you might have noticed, TxPolicies can also be specified when deploying contracts or transferring assets by passing it to the respective methods.