docs: @Internal
      public static void contributeDefaults(AnnotationMetadata target, AnnotationMetadata source) {
          if (target instanceof DefaultAnnotationMetadata && source instanceof DefaultAnnotationMetadata) {
              final Map<String, Map<CharSequence, Object>> existingDefaults = ((DefaultAnnotationMetadata) target).annotationDefaultValues;
              if (existingDefaults != null) {
                  final Map<String, Map<CharSequence, Object>> additionalDefaults = ((DefaultAnnotationMetadata) source).annotationDefaultValues;
                  if (additionalDefaults != null) {
                      existingDefaults.putAll(
                              additionalDefaults
                      );
                  }
              }
          }
      }