Purging via CNAME
Currently purging is just supported by specifying the CDN endpoint. For case where a rewrite rules is used to direct customers to different content based on the CNAME (e.g. by selecting content to return based on host name) it is valuable to have the ability to purge content based on CNAME. Without this capability one needs to create individual CDN endpoints to use for each CNAME that has different content returned based on the CNAME.