anchor.diff:  The `median` function detects anomalies in the statistical median of a value.
   The median value is calculated for each bucket.
   
  -High- and low-sided functions are not supported.
  -
   This function supports the following properties:
   
   * `field_name` (required)
  
positive.code:   "by_field_name" : "application"
  }
  --------------------------------------------------
  
  
  [float]
  
negative.code: * <<ml-metric-min,`min`>>
  * <<ml-metric-max,`max`>>
  * <<ml-metric-median,`median`>>
  * <<ml-metric-high-median,`high_median`>>
  * <<ml-metric-low-median,`low_median`>>
  * <<ml-metric-mean,`mean`>>
  * <<ml-metric-high-mean,`high_mean`>>
  * <<ml-metric-low-mean,`low_mean`>>
  