Specifies the amount of time between 2 measurement action
intervals. The action is specific to the semantic of the measure.
They are performed periodically on a sequence of results of other
measures. The period corresponds to the interval between two
successive computations of the metric. The value of
etsysSrvcLvlHistoryTimestamp result of a aggregated metric
computed corresponds to the value of the
etsysSrvcLvlHistoryTimestamp of the last metric result of the
sequence used in to compute the aggregated metric.