esaProbeStatsIntervalType is a value indicating whether this statistics row is the still-accumulating current interval or the interval that has just rolled over. Polling this flag alongside the row index is how a management station confirms it is reading the live, still-changing bin versus the frozen previous one, which matters because reading the live bin mid-update can give an inconsistent snapshot. For example, a monitoring station that sees this flag say 'current' will wait for the next rollover before archiving that row's numbers, rather than logging a half-finished interval as if it were complete.