anchor.diff:  .Set Options
   [options="header"]
   |======
  -| Name      | Required  | Default  | Description
  -| `field`   | yes       | -        | The field to insert, upsert, or update
  -| `value`   | yes       | -        | The value to be set for the field
  -| `override`| no        | true     | If processor will update fields with pre-existing non-null-valued field. When set to `false`, such fields will not be touched.
  +| Name       | Required  | Default  | Description
  +| `field` | yes       | -        | The field to insert, upsert, or update. Supports <<accessing-template-fields,template snippets>>.
  +| `value` | yes       | -        | The value to be set for the field. Supports <<accessing-template-fields,template snippets>>.
  +| `override` | no        | true     | If processor will update fields with pre-existing non-null-valued field. When set to `false`, such fields will not be touched.
   |======
   
   [source,js]
   --------------------------------------------------
   {
     "set": {
  -    "field": "field1",
  -    "value": 582.1
  +    "field": "host.os.name",
  +    "value": "{{os}}"
     }
   }
   --------------------------------------------------
  
positive.code: [options="header"]
  |======
  | Name       | Required  | Default  | Description
  | `message`  | yes       | -        | The error message of the `FailException` thrown by the processor
  |======
  
  [source,js]
  --------------------------------------------------
  {
    "fail": {
      "message": "an error message"
    }
  }
  --------------------------------------------------
  
negative.code: --------------------------------------------------
  {
    "sort": {
      "field": "array_field_to_sort",
      "order": "desc"
    }
  }
  