docs: def _dump(self):
          """dump data for an individual metric. For internal use only."""
  
          try:
              self.temp.seek(0) # seek to beginning
              arr = np.fromfile(self.temp, self.dtype)
              self.count_arr = arr['count']
              self.elapsed_arr = arr['elapsed']
  
              if self.calc_stats:
                  # calculate mean & standard deviation
                  self.count_mean = np.mean(self.count_arr)
                  self.count_std = np.std(self.count_arr)
                  self.elapsed_mean = np.mean(self.elapsed_arr)
                  self.elapsed_std = np.std(self.elapsed_arr)
  
              self._output()
          finally:
              self.temp.close()
              self._cleanup()