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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VALID, 
        INVALID, 
    };
    const ResultType m_result_type;
    const TxValidationState m_state;
    
    
    const std::optional<std::list<CTransactionRef>> m_replaced_transactions;
    
    const std::optional<CAmount> m_base_fees;
    
    explicit MempoolAcceptResult(TxValidationState state)