void Scheduler::RunLoop() {
  while (!run_queue_.IsEmpty() || !sleep_queue_.IsEmpty()) {
    if (!sleep_queue_.IsEmpty()) {
      SleepyFiber next_sleepy = sleep_queue_.GetTopFiber();
      if (std::chrono::steady_clock::now() >= next_sleepy.expected_time_) {
        next_sleepy.fiber_->SetState(FiberState::Runnable);
        Schedule(next_sleepy.fiber_);
        sleep_queue_.PopTopFiber();
      }
    }
    if (!run_queue_.IsEmpty()) {
      Fiber* next = run_queue_.PopFront();
      SwitchTo(next);
      Reschedule(next);
    }
    if (run_queue_.IsEmpty() && !sleep_queue_.IsEmpty()) {
      SleepyFiber next_sleepy = sleep_queue_.GetTopFiber();
      auto sleep_time =
          next_sleepy.expected_time_ - std::chrono::steady_clock::now();
      if (next_sleepy.expected_time_ - sleep_time <
          next_sleepy.expected_time_) {
        std::this_thread::sleep_for(next_sleepy.expected_time_ -
                                    std::chrono::steady_clock::now());
      }
    }
  }
}