Function sponsor_hash 

pub(crate) async fn sponsor_hash<N, P>(
    provider: Option<&P>,
    chain: Chain,
    tx: &mut N::TransactionRequest,
    from: Address,
    fee_payer: Option<Address>,
) -> Result<B256>
where
    N: Network,
    N::TransactionRequest: Default + FoundryTransactionBuilder<N>,
    P: Provider<N>,

Computes the sponsor hash of a built transaction, resolving the fee token for fee_payer first when one is configured. Used by --tempo.print-sponsor-hash.