saver

Saves the reading position of a state for document, so it survives a configuration change and the end of the process. rememberKiteDocViewState uses it. The viewer's scroll containers save nothing of their own, so a host that builds its own state saves it with this:

val state = rememberSaveable(book, saver = KiteDocViewState.saver(book)) { KiteDocViewState(book) }

It saves the position only: the page and scroll offset of a fixed-layout document, or a bookmark in a reflowable book. The zoom and a selection start again.