code: public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
          if (mv != null) {
              return mv.visitAnnotation(desc, visible);
          }
          return null;
      }
docs: Visits an annotation of this method.
  
  @param desc
  the class descriptor of the annotation class.
  @param visible
  <tt>true</tt> if the annotation is visible at runtime.
  @return a visitor to visit the annotation values, or <tt>null</tt> if
  this visitor is not interested in visiting this annotation.