// Assume roles with no JWT, handles AssumeRole.
	stsRouter.Methods(http.MethodPost).MatcherFunc(func(r *http.Request, rm *mux.RouteMatch) bool {
		ctypeOk := wildcard.MatchSimple("application/x-www-form-urlencoded*", r.Header.Get(xhttp.ContentType))
		authOk := wildcard.MatchSimple(signV4Algorithm+"*", r.Header.Get(xhttp.Authorization))
		noQueries := len(r.URL.RawQuery) == 0
		return ctypeOk && authOk && noQueries

		// is '.minio.sys'
		if bucket == minioMetaBucket {
			if wildcard.Match("buckets/*/.metacache/*", entry.name) {
				return nil
			}
			if wildcard.Match("tmp/*", entry.name) {
				return nil
			}
			if wildcard.Match("multipart/*", entry.name) {
				return nil
			}
			if wildcard.Match("tmp-old/*", entry.name) {
				return nil
			}
		}

   * {@code lexicographical(Collections.reverseOrder(comparator))} (consider how each would order
   * {@code [1]} and {@code [1, 1]}).
   */
  // Note: 90% of the time we don't add type parameters or wildcards that serve only to "tweak" the
  // desired return type. However, *nested* generics introduce a special class of problems that we
  // think tip it over into being worthwhile.