anchor.diff:  NOTE: The `avg` metric stores both the `sum` and `value_count` values. This lets
   you accurately average rollups over larger time intervals. For example, you can
   accurately roll up hourly averages into daily averages.
  -====
  +=====
   
   `page_size`::
   (Optional, integer)
  
positive.code: +
  .Properties of `histogram`
  [%collapsible%open]
  =====
  `fields`::
  (Required*, array of strings)
  Array of <<number,numeric>> fields to group. If you specify a `histogram`
  
negative.code: +
  .Properties of `metrics` objects
  [%collapsible%open]
  =====
  `field`::
  (Required*, string)
  <<number,Numeric>> field to collect metrics for. If you specify a `metrics`
  