class MemoryTracker
{
private:
    std::atomic<Int64> amount {0};
    std::atomic<Int64> peak {0};
    std::atomic<Int64> hard_limit {0};
    std::atomic<Int64> profiler_limit {0};

    /// 以下用于故障注入测试
    double fault_probability = 0;
    double sample_probability = 0;

    /// 父级
    std::atomic<MemoryTracker *> parent {};
……