enhancement
Problem
Example: In a value check for an attribute, you also want to access the old value to compare it with the new value, but you get the changed object in the already changed transient state. The $x.inRevision(sessionRevision()) function would allow access to the original state.
Workaround
Use inRevision(revisionAt(now()) to get the last persisted state, which then matches the session revision if the calculation is done in the editing context, thus locking the object and preventing parallel commits.
Shall
A sessionRevision() function shall return the revision of the session.