Exported for a host that takes an option's action from somewhere OTHER than the action row — a
list's double-click "that one", a keyboard shortcut. options/defaultOption hold the rich form,
onOption receives the identity, and a shortcut that forwards what it was given hands its own
handler an object where every button hands it a string. Every option === 'Next' comparison in that
handler then silently answers false.
The stable, language-free IDENTITY of an option — its
idif given, else thestringform, else the InputOption object itself. This is what crosses the notifier boundary asresults.optionand whatdefaultOption/cancelOptionare matched against.