The user of-course can already implicitly work out this information from comparing the fee-rate with the actual fee.

I think that it would be useful for people not wanting to do this arithmetic in their head.

{
    return SerializeHash(*this, SER_GETHASH, 0);
}
CTransaction::CTransaction() : nVersion(CTransaction::CURRENT_VERSION), vin(), vout(), nLockTime(0) { }
CTransaction::CTransaction(const CMutableTransaction &tx) : nVersion(tx.nVersion), vin(tx.vin), vout(tx.vout), wit(tx.wit), nLockTime(tx.nLockTime) {
    UpdateHash();
}
CTransaction& CTransaction::operator=(const CTransaction &tx) {
    *const_cast<int*>(&nVersion) = tx.nVersion;
    *const_cast<std::vector<CTxIn>*>(&vin) = tx.vin;
    *const_cast<std::vector<CTxOut>*>(&vout) = tx.vout;
    *const_cast<CTxWitness*>(&wit) = tx.wit;
    *const_cast<unsigned int*>(&nLockTime) = tx.nLockTime;
    *const_cast<uint256*>(&hash) = tx.hash;
    return *this;
}
CAmount CTransaction::GetValueOut() const
{
    CAmount nValueOut = 0;
    for (std::vector<CTxOut>::const_iterator it(vout.begin()); it != vout.end(); ++it)
    {
        nValueOut += it->nValue;
        if (!MoneyRange(it->nValue) || !MoneyRange(nValueOut))
            throw std::runtime_error(std::string(__func__) + ": value out of range");
    }
    return nValueOut;
}
double CTransaction::ComputePriority(double dPriorityInputs, unsigned int nTxSize) const