code: private static InputStream cap(final Request req) throws IOException {
          final Iterator<String> hdr = new RqHeaders.Base(req)
              .header("Content-Length").iterator();
          InputStream body = req.body();
          long length = (long) body.available();
          if (hdr.hasNext()) {
              length = Long.parseLong(hdr.next());
          }
          body = new CapInputStream(body, length);
          return body;
      }
docs: Cap the steam.
  @param req Request
  @return Stream with a cap
  @throws IOException If fails