code: public HttpClientResponseBuilder withHeader(String name, String value) {
          Action lastAction = newRule.getLastAction();
          HeaderAction headerAction = new HeaderAction(lastAction, name, value);
          newRule.overrideLastAction(headerAction);
          return this;
      }
docs: Sets response header.
  
  @param name  header name
  @param value header value
  @return response builder