This object represents the current state of this histogram
collection.
Once the histogram collection is complete the status changes
statusCaptured and the data is available for use.
None of the parameters of a histogram specification may be
modified when the specification is in statusInProgress.
A statusCaptured or statusStopped histogram must be actionClear'ed
before another histogram specification may be started.
The histogram may be read accurately between the cwrUpdateRate
intervals. If the read spans across the update time data from the
previous and current updates can be mingled.