code: func RoundTrip(x *interface{}) error {
  	bs, err := json.Marshal(x)
  	if err != nil {
  		return err
  	}
  	return UnmarshalJSON(bs, x)
  }
docs: // RoundTrip encodes to JSON, and decodes the result again.
  //
  // Thereby, it is converting its argument to the representation expected by
  // rego.Input and inmem's Write operations. Works with both references and
  // values.