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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uint256 hash = *it;
                        CInv inv(state.m_wtxid_relay ? MSG_WTX : MSG_TX, hash);
                        
                        pto->m_tx_relay->setInventoryTxToSend.erase(it);
                        
                        if (pto->m_tx_relay->filterInventoryKnown.contains(hash)) {
                            continue;
                        }
                        
                        auto txinfo = m_mempool.info(ToGenTxid(inv));
                        if (!txinfo.tx) {
                            continue;
                        }
                        auto txid = txinfo.tx->GetHash();
                        auto wtxid = txinfo.tx->GetWitnessHash();
                        
                        if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) {
                            continue;
                        }
                        if (pto->m_tx_relay->pfilter && !pto->m_tx_relay->pfilter->IsRelevantAndUpdate(*txinfo.tx)) continue;
                        
                        State(pto->GetId())->m_recently_announced_invs.insert(hash);
                        vInv.push_back(inv);
                        nRelayedTransactions++;
                        {
                            
                            while (!g_relay_expiration.empty() && g_relay_expiration.front().first < current_time)
                            {
                                mapRelay.erase(g_relay_expiration.front().second);
                                g_relay_expiration.pop_front();