When the wallet is rescanned at startup in `bitcoind`, there seems to be no way to interrupt that in a clean way (other than forcefully killing the process).
LOCK2(cs_main, cs_wallet);
    CReserveKey reservekey(this);
    CTransactionRef tx_new;
    if (!CreateTransaction(vecSend, tx_new, reservekey, nFeeRet, nChangePosInOut, strFailReason, coinControl, false)) {
        return false;
    }
    if (nChangePosInOut != -1) {
        tx.vout.insert(tx.vout.begin() + nChangePosInOut, tx_new->vout[nChangePosInOut]);
        
        
        reservekey.KeepKey();
    }
    
    
    for (unsigned int idx = 0; idx < tx.vout.size(); idx++) {
        tx.vout[idx].nValue = tx_new->vout[idx].nValue;
    }
    
    for (const CTxIn& txin : tx_new->vin) {
        if (!coinControl.IsSelected(txin.prevout)) {
            tx.vin.push_back(txin);
            if (lockUnspents) {
                LockCoin(txin.prevout);
            }
        }
    }
    return true;
}
OutputType CWallet::TransactionChangeType(OutputType change_type, const std::vector<CRecipient>& vecSend)