Checkpointing can mean slightly different things:
- Resuming sampling such that the entire state of the random number generator is reinstated, yielding numerically identical samples as if you hadn’t stopped.
- Resuming sampling such that you don’t “lose work” in the sampler’s efforts to adapt, but don’t reinstate the full RNG state and thereby yield functionally equivalent but not-numerically-identical samples as if you hadn’t stopped.
I don’t believe that any of the interfaces achieve 1, and while you can do 2, it’s a bit of a manual process at present.