Define OpenAPI 3.x `trace` [Path Iem](https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.2.md#pathItemObject) operation elements in an OpenAPI 2.0 API description document. This allows converting OpenAPI 2.0 to OpenAPI 3.0 for tools which work with OpenAPI 3.0.

                        {"paths":{"/books":{"x-trace":{"operationId":"books-trace","desription":"The TRACE HTTP operation for the books resource.","responses":"..."}}}}