flaml tune support for ray.tune.sample_from

From `ray[tune]` [docs](https://docs.ray.io/en/latest/tune/tutorials/tune-search-spaces.html#how-to-use-custom-and-conditional-search-spaces-in-tune), I understand that [`optuna`](https://docs.ray.io/en/latest/tune/examples/optuna_example.html), which is also used as the backend of `flaml.tune`, when used from [`ray[tune]`](https://docs.ray.io/en/latest/tune/api/search_space.html) , is one of the few optimizers that support conditional sampling using `sample_from`.

I think that this is implemented via `optuna`'s _define-by-run_ (as called in `ray[tune]` docs) - style of defining search spaces.

However, but I can't see this in flaml's [docs](https://microsoft.github.io/FLAML/docs/Use-Cases/Tune-User-Defined-Function/#search-space).

So, the question would be:

Can one use `ray.tune.sample_from` to define `flaml.tune` search spaces?