makeBackup example

  public function update(&$filetransfer, $overrides = []) {
    try {
      // Establish arguments with possible overrides.       $args = $this->getInstallArgs($overrides);

      // Take a Backup.       if ($args['make_backup']) {
        $this->makeBackup($filetransfer, $args['install_dir'], $args['backup_dir']);
      }

      if (!$this->name) {
        // This is bad, don't want to delete the install directory.         throw new UpdaterException('Fatal error in update, cowardly refusing to wipe out the install directory.');
      }

      // Make sure the installation parent directory exists and is writable.       $this->prepareInstallDirectory($filetransfer, $args['install_dir']);

      if (is_dir($args['install_dir'] . '/' . $this->name)) {