The kind of measurement. It describes how the data is reported. For information on setting the start time and end time based on the MetricKind, see [TimeInterval][google.monitoring.v3.TimeInterval].

METRIC_KIND_UNSPECIFIED Do not use this default value.
GAUGE An instantaneous measurement of a value.
DELTA The change in a value during a time interval.
CUMULATIVE A value accumulated over a time interval. Cumulative measurements in a time series should have the same start time and increasing end times, until an event resets the cumulative value to zero and sets a new start time for the following points.