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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if (pfrom.HasPermission(NetPermissionFlags::Addr)) {
            vAddr = m_connman.GetAddresses(MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND,  std::nullopt);
        } else {
            vAddr = m_connman.GetAddresses(pfrom, MAX_ADDR_TO_SEND, MAX_PCT_ADDR_TO_SEND);
        }
        FastRandomContext insecure_rand;
        for (const CAddress &addr : vAddr) {
            PushAddress(*peer, addr, insecure_rand);
        }
        return;
    }
    if (msg_type == NetMsgType::MEMPOOL) {
        if (!(pfrom.GetLocalServices() & NODE_BLOOM) && !pfrom.HasPermission(NetPermissionFlags::Mempool))
        {
            if (!pfrom.HasPermission(NetPermissionFlags::NoBan))
            {
                LogPrint(BCLog::NET, "mempool request with bloom filters disabled, disconnect peer=%d\n", pfrom.GetId());
                pfrom.fDisconnect = true;
            }
            return;
        }
        if (m_connman.OutboundTargetReached(false) && !pfrom.HasPermission(NetPermissionFlags::Mempool))
        {
            if (!pfrom.HasPermission(NetPermissionFlags::NoBan))
            {
                LogPrint(BCLog::NET, "mempool request with bandwidth limit reached, disconnect peer=%d\n", pfrom.GetId());
                pfrom.fDisconnect = true;
            }
            return;
        }