code: protected function popStack()
      {
          $stackInfo = \array_pop($this->funcStack);
          $funcPopped = $stackInfo['function'];
          $timeElapsed = \microtime(true) - $stackInfo['tsStart'];
          $this->data[$funcPopped]['ownTime'] += $timeElapsed - $stackInfo['subTime'];
          $this->data[$funcPopped]['totalTime'] += $timeElapsed;
          if ($this->data[$funcPopped]['calls'] === 0) {
              $this->data[$funcPopped]['calls'] ++;
          }
          if ($this->funcStack) {
              $this->funcStack[\count($this->funcStack)-1]['subTime'] += $timeElapsed;
          }
          return $stackInfo['function'];
      }
docs: Remove function from stack and add time to profile
  
  @return string name of popped function