anchor.diff:  
   -opaque t() ::
       #t{}.
  -
  -
  --define(SERIALIZATION_KEY_REALM, <<"realm">>).
  --define(SERIALIZATION_KEY_URI  , <<"uri">>).
   
   
   -spec cons(realm(), uri()) ->
  
positive.code:     % Access
      , get_realm/1
      , get_uri/1
  
      % Serialize (for internal storage purposes only!)
      , to_props/1
      , of_props/1
      ]).
  
  
  
negative.code:     uri().
  get_uri(#t{uri=URI}) ->
      URI.
  