code: public <T extends Feature<T>> T feature(FeatureType<T> featureType) {
      return source.feature(featureType);
    }
docs: Returns the instance of {@code featureType} appropriate for the source being written. For
  instance, <code>code.feature({@link GuavaLibrary#GUAVA
  GUAVA}).{@link GuavaLibrary#isAvailable() isAvailable()}</code> returns true if the Guava
  library can be used in the generated source code.
  
  <p>Fluent extension point for features dynamically determined based on the current
  {@link ProcessingEnvironment}.
  
  @see Feature