public Builder backupStrategy(BackupStrategy backupStrategy) {
      if (!(backupStrategy instanceof BackupStrategy2)) {
        backupStrategy = new BackupStrategyWrapper(backupStrategy);
      }
      this.backupStrategy = (BackupStrategy2) backupStrategy;

      BackupUtil.verifyBackupStrategy(this.backupStrategy);
      return this;
    }
Set the backup strategy for log file.

@param backupStrategy the backup strategy for log file
@return the builder
xlog/src/main/java/com/elvishew/xlog/printer/file/FilePrinter.java