@Nonnull @Override public Response handle(@Nonnull final Context context) throws Exception { // Ensure the extra handlers are inserted only once, in the case that a handler higher // on the stack calls proceed() twice for some reason if (!isMarkedExtended(context)) { ListIterator<ContributedHandler> handlerIterator = contributedHandlers.listIterator(contributedHandlers.size()); while (handlerIterator.hasPrevious()) { context.insertHandler(handlerIterator.previous()); } markExtended(context); } return context.proceed(); }