Enabling the Address attribute in the SubjectConfirmationData element

[Dave Rager]

I'm setting up SimpleSAMLphp as an IDP. Everything is mostly working
except in the SubjectConfirmationData I cannot figure out how to
enable the Address attribute.

From the spec:

It MAY contain an Address attribute limiting the client address
from which the assertion can be delivered.

Indeed, I want to do that.

I see support for the attribute in the source code though I cannot
find documentation about it. I don’t see anywhere in the source that
it actually gets set. (Outside reading an incoming response).

What configuration setting do I need to enable this attribute or is it
supported only to handle it in incoming responses?

Thanks,
Dave.