Service metadata response

Is there an example of the Service Metadata response (xml doc) that must be returned for the https://<ip>/redfish/v1/$metadata URL ?

Specifically, I couldn't find concrete examples of the edmx:Schema tag must be formatted.

Please provide an illustration complete with all elements of the metadata response including:
1) Standard Redfish resources and Services.
2) OEM extension collections and/or resources.

Thanks!