text: #pragma once
  #include <chrono>
  namespace DRL {
  
  class HRTimer {
  public:
    HRTimer();
    void start() { start_ = clock_::now(); }
  
    void end();
  
    double elapsed() const;
    void reset();
  
  private:
    using clock_ = std::chrono::high_resolution_clock;
    decltype(clock_::now()) start_;
    decltype(clock_::now()) end_;
  };
  } // namespace DRL
  