code: public function get()
      {
          if (!$this->queue->isEmpty()) {
              return $this->queue->pop();
          }
  
          if ($this->maxSize > 0 && $this->count() >= $this->maxSize) {
              throw new \RuntimeException(
                  "Server busy, no resources available.(The pool has been overflow max value: {$this->maxSize})"
              );
          }
  
          return ($this->creator)();
      }
docs: {@inheritdoc}
  @throws \RuntimeException