code: public DocServiceBuilder exampleHttpHeaders(String serviceName,
                                                  Iterable<? extends HttpHeaders> exampleHttpHeaders) {
          requireNonNull(serviceName, "serviceName");
          checkArgument(!serviceName.isEmpty(), "serviceName is empty.");
          requireNonNull(exampleHttpHeaders, "exampleHttpHeaders");
          return exampleHttpHeaders0(serviceName, "", exampleHttpHeaders);
      }
docs: Adds the example {@link HttpHeaders} for the service with the specified name.