code: public function destroy(string $sessionIdentifier): void
      {
          if (!isset(self::$files[$sessionIdentifier])) {
              throw new SessionNotFoundException();
          }
  
          unset(self::$files[$sessionIdentifier]);
      }
docs: Remove this session from the storage.
  
  @throws \PHPSess\Exception\SessionNotFoundException
  @param  string $sessionIdentifier The session identifier.
  @return void