anchor.diff:  `uptimeRatio` is basically a percentage of the time for the duration of the bucket that the metric is up. The value
   will be a floating point number between zero and one.
   
  -`downtimeCount` is the number of times within the duration of the bucket that the metric was reported down.
  +`downtimeCount` is the number of periods in which a resource is reported down. In this context a period is a range of
  +consecutive data points in which the availability does not change. For example, if a resource reports down twice in a
  +row, then up, and then down again, `downtimeCount` will be 2.
   
   Now let's look at what an empty data point looks like.
   
  
positive.code: an empty bucket next.
  
  `downtimeDuration` is the total time in milliseconds that the metric was reported down. Note that this is the total
  time within the bucket's stat and end times.
  
  `lastDowntime` is the last time within the bucket's time range that the metric was reported down. The value is in
  milliseconds.
  
negative.code: [source,shell]
  .Fetch rate stats using bucketDuration parameter
  ----
  curl -X GET http://server/hawkular/metrics/counters/total_requests/rate/stats?start=1235&end=6789&bucketDuration=1mn \
  -H "Content-Type: application/json" -H "Hawkular-Tenant: com.acme"
  ----
  
  