  HeaderMap& headersOrTrailers() override {
    if (absl::holds_alternative<RequestHeaderMapPtr>(headers_or_trailers_)) {
      return *absl::get<RequestHeaderMapPtr>(headers_or_trailers_);
    } else {
      return *absl::get<RequestTrailerMapPtr>(headers_or_trailers_);
    }
  }
  HeaderMap& headersOrTrailers() override {
    if (absl::holds_alternative<RequestHeaderMapPtr>(headers_or_trailers_)) {
      return *absl::get<RequestHeaderMapPtr>(headers_or_trailers_);
    } else {
      return *absl::get<RequestTrailerMapPtr>(headers_or_trailers_);
    }
  }