For software that interfaces with Bitcoin Core via RPC, it can be useful to know whether the fRelayTxes flag is set. It could be added to `getnetworkinfo`.

if (hashIn != hashTmp)
        return error("%s: Checksum mismatch, data corrupted", __func__);
    unsigned char pchMsgTmp[4];
    try {
        
        ssPeers >> FLATDATA(pchMsgTmp);
        
        if (memcmp(pchMsgTmp, Params().MessageStart(), sizeof(pchMsgTmp)))
            return error("%s: Invalid network magic number", __func__);
        
        ssPeers >> addr;
    }
    catch (const std::exception& e) {
        return error("%s: Deserialize or I/O error - %s", __func__, e.what());
    }
    return true;
}
unsigned int ReceiveFloodSize() { return 1000*GetArg("-maxreceivebuffer", DEFAULT_MAXRECEIVEBUFFER); }
unsigned int SendBufferSize() { return 1000*GetArg("-maxsendbuffer", DEFAULT_MAXSENDBUFFER); }
CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNameIn, bool fInboundIn) :
    ssSend(SER_NETWORK, INIT_PROTO_VERSION),
    addrKnown(5000, 0.001),
    filterInventoryKnown(50000, 0.000001)
{
    nServices = 0;
    hSocket = hSocketIn;
    nRecvVersion = INIT_PROTO_VERSION;
    nLastSend = 0;
    nLastRecv = 0;
    nSendBytes = 0;