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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bPingFinished = true;
            sProblem = "Short payload";
        }
        if (!(sProblem.empty())) {
            LogPrint(BCLog::NET, "pong peer=%d: %s, %x expected, %x received, %u bytes\n",
                pfrom.GetId(),
                sProblem,
                peer->m_ping_nonce_sent,
                nonce,
                nAvail);
        }
        if (bPingFinished) {
            peer->m_ping_nonce_sent = 0;
        }
        return;
    }
    if (msg_type == NetMsgType::FILTERLOAD) {
        if (!(pfrom.GetLocalServices() & NODE_BLOOM)) {
            LogPrint(BCLog::NET, "filterload received despite not offering bloom services from peer=%d; disconnecting\n", pfrom.GetId());
            pfrom.fDisconnect = true;
            return;
        }
        CBloomFilter filter;
        vRecv >> filter;
        if (!filter.IsWithinSizeConstraints())
        {
            
            Misbehaving(pfrom.GetId(), 100, "too-large bloom filter");
        }
        else if (pfrom.m_tx_relay != nullptr)