This read-only DisplayString reports the time at which this history bin's counters were last cleared, per its description, which may differ from its collection start time if the bin was manually reset, via cienaCesPmInstanceClear or cienaCesPmInstanceHistoryClear, partway through its normal collection period. This distinction matters because a bin whose clear time is well after its start time contains counts only from the portion of the period since the reset, not the bin's full nominal duration, which affects how any rate calculations from that bin's data should be interpreted. An engineer computing an average throughput from a bin's byte count would check this clear time against the bin duration to confirm the counts actually cover the full expected interval rather than a partial, post-clear window.