Joshua Marner

LGTM

@TysonMN no I flipped the order. Merge #471 first now

Converting to draft until #472 is merged in.

@the-not-mad-psychologist > Why always the `ValueOption.map box >> ValueOption.toObj >> unbox` sequence? Does type safety interfere with `ValueOption.toObj` somehow? What it does is handle both cases where `'a` is nullable...

Converting into draft until #474 is merged in. Also added tests (enabled by #474)

@TysonMN I had to revert some of the changes from [PR 474](https://github.com/elmish/Elmish.WPF/pull/474#issuecomment-1159901957) that you added because they moved the `box` functions into `BindingData` which breaks this PR. That boxing now...

@TysonMN The [second commit (7bce311)](https://github.com/elmish/Elmish.WPF/pull/470/commits/7bce311d2f900e28c7fe298b2f77eb20b69a8fe1) moves all of the `box` and `unbox` calls into `BindingData.mapVm`

@TysonMN added in #495

@TysonMN this test failure isn't real. The check needs to be re-run.

@TysonMN it's currently always impossible in `DynamicViewModel` because the type of `'vm` is always `obj`, which is always nullable. As to where it is used, `ValueOption.toNull` is used in 3...