docs: public Long getFileSizeAvg() {
          Long fileSizeAvg = 0L;
          if (items.size() != 0) {
              for (TableStat item : items) {
                  if (item.getEndTime().equals(item.getStartTime())) {
                      fileSizeAvg += item.getFileSize();
                  } else {
                      fileSizeAvg += item.getFileSize() * 1000
                                     / (item.getEndTime().getTime() - item.getStartTime().getTime());
                  }
              }
              fileSizeAvg = fileSizeAvg / items.size();
          }
          return fileSizeAvg;
      }