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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m_addrman.Good(pfrom.addr);
        }
        std::string remoteAddr;
        if (fLogIPs)
            remoteAddr = ", peeraddr=" + pfrom.addr.ToString();
        LogPrint(BCLog::NET, "receive version message: %s: version %d, blocks=%d, us=%s, txrelay=%d, peer=%d%s\n",
                  cleanSubVer, pfrom.nVersion,
                  peer->m_starting_height, addrMe.ToString(), fRelay, pfrom.GetId(),
                  remoteAddr);
        int64_t nTimeOffset = nTime - GetTime();
        pfrom.nTimeOffset = nTimeOffset;
        AddTimeData(pfrom.addr, nTimeOffset);
        
        if (greatest_common_version <= 70012) {
            CDataStream finalAlert(ParseHex("60010000000000000000000000ffffff7f00000000ffffff7ffeffff7f01ffffff7f00000000ffffff7f00ffffff7f002f555247454e543a20416c657274206b657920636f6d70726f6d697365642c2075706772616465207265717569726564004630440220653febd6410f470f6bae11cad19c48413becb1ac2c17f908fd0fd53bdc3abd5202206d0e9c96fe88d4a0f01ed9dedae2b6f9e00da94cad0fecaae66ecf689bf71b50"), SER_NETWORK, PROTOCOL_VERSION);
            m_connman.PushMessage(&pfrom, CNetMsgMaker(greatest_common_version).Make("alert", finalAlert));
        }
        
        if (pfrom.IsFeelerConn()) {
            LogPrint(BCLog::NET, "feeler connection completed peer=%d; disconnecting\n", pfrom.GetId());
            pfrom.fDisconnect = true;
        }
        return;
    }
    if (pfrom.nVersion == 0) {