Simulate a transaction

func handleSimulateTransaction() {
    // First, create a transaction.
    let transaction = SimulateTransactionParam(
        to: "0xRecipientAddressHere", // The recipient address.
        value: "0x10DE4A2A",          // The value to be sent in Wei.
        data: nil,                    // Data for the transaction (for contract interactions).
        maxFeePerGas: nil,            // Maximum fee per gas.
        maxPriorityFeePerGas: nil,    // Maximum priority fee per gas.
        gas: nil,                     // The gas limit.
        gasPrice: nil                 // Gas price in Wei.
    )

    // Next, simulate the transaction.
    portal?.api.simulateTransaction(transaction: transaction) {
        (result: Result<SimulatedTransaction>) in

        // Check for general errors.
        if let error = result.error {
            print("❌ Error simulating transaction:", error)
            return
        }

        // Safely unwrap the simulated result.
        guard let simulatedResult = result.data else {
            print("❌ Unexpected error: result data is nil.")
            return
        }

        // Finally, you can handle or display the simulation results as needed.
        if let requestError = simulatedResult.requestError {
            print("❌ Request error:", requestError.message)
        } else if let error = simulatedResult.error {
            print("✅ Transaction will have error:", error.message)
        } else {
            print("✅ Simulated transaction changes:", simulatedResult.changes)
        }
    }
}