docs: final void roll(final long timeForSuffix) {
  
      final File backupFile = this.prepareBackupFile(timeForSuffix);
  
      // close filename
      this.getAppender().closeFile();
  
      // rename filename on disk to filename+suffix(+number)
      this.doFileRoll(this.getAppender().getIoFile(), backupFile);
  
      // setup new file 'filename'
      this.getAppender().openFile();
  
      this.fireFileRollEvent(new FileRollEvent(this, backupFile));
    }