Migrating DNS from an existing service to Static Web Apps

Hi there,

Not sure if this is a feature request or something that is missing in the documentation but I'm having trouble migrating an existing site to a Static Web App...

I have a site currently hosted on-prem which is `websiteA.domain.com`. The DNS is currently CNamed to our web server.

I want to move it to a Static Web App I have in Azure.

Unfortunately the two ways of verifying will cause some downtime as far as I can tell:

CNAME Verification
I would need to re-point the CNAME from the existing web server to Azure, In the time between me making the change and Azure verifying the record (normally quick, sometimes not) people will get an error going to the site.
TXT Verification
I use Azure DNS and it doesn't support both a CNAME and TXT record pointing to the same subdomain, so I would need to remove the record entirely to do this, which is even less ideal than CNAME.

For things like App Services you can point a TXT record to `asuid.websiteA.domain.com` which would suit my needs but it doesn't seem to be a thing for SWA as far as I can see.

Is there an undocumented solution for this?
If not, the feature request would be to add verification on a subdomain e.g. `asuid.websiteA.domain.com` so we can do smoother migrations from existing sites.