message: Explicitly convert absl::string_view to std::string.
diff: @@ -39,7 +39,7 @@ struct SuccessResponse {
  if (context->matchers_->matches(header.key().getStringView())) {
  context->response_->headers_to_add.emplace_back(
  Http::LowerCaseString{std::string(header.key().getStringView())},
  - header.value().getStringView());
  + std::string(header.value().getStringView()));
  }
  return Http::HeaderMap::Iterate::Continue;
  },
  