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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return;
    }
    
    
    if (!(pindex->nStatus & BLOCK_HAVE_DATA)) {
        return;
    }
    std::shared_ptr<const CBlock> pblock;
    if (a_recent_block && a_recent_block->GetHash() == pindex->GetBlockHash()) {
        pblock = a_recent_block;
    } else if (inv.IsMsgWitnessBlk()) {
        
        
        std::vector<uint8_t> block_data;
        if (!ReadRawBlockFromDisk(block_data, pindex, m_chainparams.MessageStart())) {
            assert(!"cannot load block from disk");
        }
        m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::BLOCK, MakeSpan(block_data)));
        
    } else {
        
        std::shared_ptr<CBlock> pblockRead = std::make_shared<CBlock>();
        if (!ReadBlockFromDisk(*pblockRead, pindex, m_chainparams.GetConsensus())) {
            assert(!"cannot load block from disk");
        }
        pblock = pblockRead;
    }
    if (pblock) {
        if (inv.IsMsgBlk()) {
            m_connman.PushMessage(&pfrom, msgMaker.Make(SERIALIZE_TRANSACTION_NO_WITNESS, NetMsgType::BLOCK, *pblock));