code: private function storeCurrentCell()
      {
          if ($this->currentCellIsDirty && !empty($this->currentCoordinate)) {
              $this->currentCell->detach();
  
              $stored = $this->cache->set($this->cachePrefix . $this->currentCoordinate, $this->currentCell);
              if (!$stored) {
                  $this->__destruct();
  
                  throw new PhpSpreadsheetException("Failed to store cell {$this->currentCoordinate} in cache");
              }
              $this->currentCellIsDirty = false;
          }
  
          $this->currentCoordinate = null;
          $this->currentCell = null;
      }
docs: Store cell data in cache for the current cell object if it's "dirty",
  and the 'nullify' the current cell object.
  
  @throws PhpSpreadsheetException