State transfer
Two values, computed identically. One was declared saveable and crossed from the server; the other was not and was recomputed here.
saveable-from-215379
plain-from-215379
rendered-by-215379
Read the three numbers
The last line is this browser's instance. If the first line differs from it, that value was produced on the server and travelled here inside the document. The middle line always matches the last, because a plain remember has nothing carrying it.
Built on Compose, not beside it
This uses Compose's own SaveableStateRegistry rather than a bespoke serialiser. It brings the right discipline with it: state crosses the boundary when its author wrote rememberSaveable, and only then. Everything else is recomputed, which is the documented behaviour rather than a gap.