title: Use dart reflectable on external lib
body: <p>I need to use reflectable on a third party lib but it is not working.</p>
  
  <p>Consider this scenario:</p>
  
  <p>Library A has the reflector declaration:</p>
  
  <pre><code>class Reflector extends Reflectable {
      const Reflector()
          : super(invokingCapability,
          typeRelationsCapability,
          metadataCapability,
          superclassQuantifyCapability,
          reflectedTypeCapability);
  }
  
  const Reflector reflector = const Reflector();
  </code></pre>
  
  <p>Library B has the classes that are annotated with the reflector: </p>
  
  <pre><code>import 'package:library_a/library_a.dart' show reflector;
  
  @reflector
  class whateverz {}
  </code></pre>
  
  <p>Now the application C needs to use reflection on whateverz class that is within library B.  </p>
  
  <p>My problem is that the reflectable lib can't see the whateverz class annotated. The build warns "reflector.dart: This reflector does not match anything"</p>
  
  <p>And if I do "print(reflector.annotatedClasses);" it prints [] within the console.</p>
  
  <p>Is this possible? To annotate the classes on a third party lib that I will end up using in an application with reflection?
  If yes, what am I doing wrong?</p>