12 std::chrono::time_point<std::chrono::high_resolution_clock>
realtime_end;
std::chrono::time_point< std::chrono::high_resolution_clock > realtime_start
friend std::ostream & operator<<(std::ostream &os, const Timer &)
std::clock_t cputime_start
std::chrono::time_point< std::chrono::high_resolution_clock > realtime_end