@Retention(value=RUNTIME)
@Target(value=FIELD)
public @interface NotBindable
final. In fact, if a BindableModel has a field that is not marked
final, a runtime error will during the call to Bindings.bind(Object). To
allow BindableModels to have non-final fields, mark those fields with this annotation.
It can be thought of as similar to SuppressWarnings as a way to force the coder
to explicitly specify intention when doing something dangerous.