ContentState.kt

spec {
    // ContentState
    inState<GithubState.ContentState> {
        on { action: GithubAction.TypeOwner, state: State<GithubState.ContentState> ->
            state.mutate { copy(owner = action.input) }
        }

        on { _: GithubAction.Confirm, state: State<GithubState.ContentState> ->
            val owner = state.snapshot.owner
            if (owner.isNotBlank()) {
                state.override { GithubState.Load(owner = owner) }
            } else {
                state.noChange()
            }
        }
    }
    //...
}