code: private static Response wrap(final Response res, final Fallback fbk,
          final Request req) {
          // @checkstyle AnonInnerLengthCheck (50 lines)
          return new Response() {
              @Override
              public Iterable<String> head() throws IOException {
                  final long start = System.currentTimeMillis();
                  Iterable<String> head;
                  try {
                      head = res.head();
                  } catch (final HttpException ex) {
                      head = fbk.route(
                          TkFallback.fallback(req, start, ex, ex.code())
                      ).get().head();
                  } catch (final Throwable ex) {
                      head = fbk.route(
                          TkFallback.fallback(
                              req, start, ex,
                              HttpURLConnection.HTTP_INTERNAL_ERROR
                          )
                      ).get().head();
                  }
                  return head;
              }
  
              @Override
              public InputStream body() throws IOException {
                  final long start = System.currentTimeMillis();
                  InputStream body;
                  try {
                      body = res.body();
                  } catch (final HttpException ex) {
                      body = fbk.route(
                          TkFallback.fallback(req, start, ex, ex.code())
                      ).get().body();
                  } catch (final Throwable ex) {
                      body = fbk.route(
                          TkFallback.fallback(
                              req, start, ex,
                              HttpURLConnection.HTTP_INTERNAL_ERROR
                          )
                      ).get().body();
                  }
                  return body;
              }
          };
      }
docs: Wrap response.
  @param res Response to wrap
  @param fbk Fallback
  @param req Request
  @return Response