This probably means similar to 3rd party handling of the SSL connection with an AV acting as man in the middle as such, may have a bit of an overhead, not sure if that would be similar to the old avast 8 mail shield handling of SSL mail or the web shield proxy.

As far as I’m aware avast have mentioned they are planning to be able to do this in a future version of avast, but nothing as far as time frame or version.