code: public function unlock(string $sessionIdentifier): void
      {
          $index = array_search($sessionIdentifier, self::$lockedIdentifiers);
  
          if ($index !== false) {
              unset(self::$lockedIdentifiers[$index]);
          }
      }
docs: Asks the drive to unlock the session storage
  
  @param string $sessionIdentifier The session identifier to be unlocked
  @return void