code: public Annotation asAnnotation() {
        if (this instanceof Annotation) {
           return Cast.as(this);
        } else if (document() != null) {
           return document()
                     .annotationBuilder()
                     .type(AnnotationType.ROOT)
                     .bounds(this)
                     .attributes(this)
                     .createDetached();
        }
        return Fragments.detachedAnnotation(AnnotationType.ROOT, start(), end());
     }
docs: Gets this HString as an annotation. If the HString is already an annotation it is simply cast. Otherwise a
  detached annotation of type <code>AnnotationType.ROOT</code> is created.
  
  @return An annotation.