code: @SuppressWarnings("unchecked")
      public static <T> T touch(T msg) {
          if (msg instanceof ReferenceCounted) {
              return (T) ((ReferenceCounted) msg).touch();
          }
          return msg;
      }
docs: Tries to call {@link ReferenceCounted#touch()} if the specified message implements {@link ReferenceCounted}.
  If the specified message doesn't implement {@link ReferenceCounted}, this method does nothing.