This example was incorrectly throwing away results from a query when multiple queries were pending at once.   Thanks to @sun-jiao in https://github.com/flutter/flutter/pull/127019#issuecomment-1552347037 for pointing this out.

I also added a quick  `Text` widget explaining what to do to use the examples.  Since there are only three small possible `options`, it's easy to type into the field and not get any results and wonder what's wrong.