Function build_simulation_signed_fee_payer 

pub fn build_simulation_signed_fee_payer(
    fee_payer_txn: &FeePayerRawTransaction,
) -> SignedTransaction

Builds a signed transaction for simulation only (fee-payer / sponsored).

Uses AccountAuthenticator::NoAccountAuthenticator for all signers (sender, secondary signers, and fee payer) so that the transaction can be sent to the simulate endpoint without real signatures. Use this to simulate a fee-payer transaction before collecting signatures.

Example

let fee_payer_txn = FeePayerRawTransaction::new_simple(raw_txn, fee_payer_address);
let signed = build_simulation_signed_fee_payer(&fee_payer_txn);
let result = aptos.simulate_signed(&signed).await?;