docs: private static String formatTime(int length, long time) {
          Calendar cal = Calendar.getInstance();
          if (time > -1) cal.setTimeInMillis(time);
          StringBuilder sb = new StringBuilder(length);
          int month = cal.get(Calendar.MONTH) + 1;
          int day = cal.get(Calendar.DAY_OF_MONTH);
          int hour = cal.get(Calendar.HOUR_OF_DAY);
          int minute = cal.get(Calendar.MINUTE);
          int seconds = cal.get(Calendar.SECOND);
          sb.append(cal.get(Calendar.YEAR)).append('-');
          if (month < 10) sb.append('0');
          sb.append(month).append('-');
          if (day < 10) sb.append('0');
          sb.append(day).append(' ');
          if (hour < 10) sb.append('0');
          sb.append(hour).append(':');
          if (minute < 10) sb.append('0');
          sb.append(minute).append(':');
          if (seconds < 10) sb.append('0');
          sb.append(seconds);
          if (length > 20) {
              int millis = cal.get(Calendar.MILLISECOND);
              sb.append('.');
              if (millis < 10) {
                  sb.append("00");
              } else if (millis < 100) {
                  sb.append('0');
              }
              sb.append(millis);
          }
          return sb.toString();
      }