anchor.diff:  - `type` is required and constrained to 255 characters
   - `relatedEntityReferenceType` is required and constrained to a valid EntityReferenceType value defined in
   [data types](https://github.com/snapbundle/sdk/blob/master/DATA_TYPES.md "Data Types")
  -- `relatedReferenceURN` must point to a pre-existing record of the given `relatedEntityReferenceType`
  +- `relatedReferenceUrn` must point to a pre-existing record of the given `relatedEntityReferenceType`
   - `moniker` is optional and constrained to 2048 characters may be omitted; defaults to **null**
   
   #### Idempotent Behavior
  
positive.code:                 "referenceUrn" : "urn:uuid:12345",
                  "type" : "Owns",
                  "relatedEntityReferenceType": "Object",
                  "relatedReferenceURN" : "urn:uuid:54321",
                  "lastModifiedTimestamp" : 1390607277299,
              }
  
  
negative.code: referenceUrn | String | true | false | Minimum |
  type | String | true | false | Minimum |
  relatedEntityReferenceType | EntityReferenceType | true | false | Minimum |
  relatedReferenceUrn | String | true | false | Minimum |
  
  ### Field Notes
  - The `entityReferenceType` and `referenceUrn` fields jointly represent the *owner* or *initiator* of the relationship
  - The `relatedEntityReferenceType` and `relatedReferenceUrn` fields jointly represent the *subordinate* member of the relationship
  - The `type` field is available to create an ontology or high level categories that can be used to group related relationships.
  The platform makes no inferences about this case-sensitive field.
  
  