There are some potential feefilter cleanups mentioned and motivated in comment https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-805808485 . If you address the locking one, please be careful and make sure that `round()` is only called under a lock. See https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-807992199

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* Bitcoin Core P2P design
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}
        return;
    }
    
    
    if (msg_type == NetMsgType::SENDADDRV2) {
        if (pfrom.fSuccessfullyConnected) {
            
            LogPrint(BCLog::NET, "sendaddrv2 received after verack from peer=%d; disconnecting\n", pfrom.GetId());
            pfrom.fDisconnect = true;
            return;
        }
        peer->m_wants_addrv2 = true;
        return;
    }
    if (!pfrom.fSuccessfullyConnected) {
        LogPrint(BCLog::NET, "Unsupported message \"%s\" prior to verack from peer=%d\n", SanitizeString(msg_type), pfrom.GetId());
        return;
    }
    if (msg_type == NetMsgType::ADDR || msg_type == NetMsgType::ADDRV2) {
        int stream_version = vRecv.GetVersion();
        if (msg_type == NetMsgType::ADDRV2) {
            
            
            stream_version |= ADDRV2_FORMAT;
        }
        OverrideStream<CDataStream> s(&vRecv, vRecv.GetType(), stream_version);
        std::vector<CAddress> vAddr;
        s >> vAddr;
        if (!RelayAddrsWithPeer(*peer)) {