XDCR should allow filtering expression on expiration (or expiry)

Despite the fact XDCR allows setting expiration (or expiry) on the destination XDCR does not allow filtering on expiration.

we should be able to build expressions like the following.
REGEXP_CONTAINS(META().id, "airport") AND (META().expiration = 0)
The above might be used in conjunction with say an Eventing that rests the TTL to avoid a double mutation race.   Regardless of Eventing use cases there is other utility to exposing this filed and perhaps others form META

It seems there is a very limited set of fields form META that can actually be used.