Function snapps_txn_reference_impl::update_logic::apply_delegate_update

pub fn apply_delegate_update<'a>(
    account: Account<'a>, 
    update: &PartyUpdate<'_>
) -> Account<'a>

Update the delegate field of account::Account with the new value from the party::PartyUpdate.

Using set_or_keep:

account.delegate = set_or_keep(account.delegate, update.delegate)