public:
  GrpcServiceMethodToRequestNamesMap(Stats::SymbolTable& symbol_table)
      : stat_name_pool_(symbol_table) {}

  void populate(const envoy::config::core::v3::GrpcMethodList& method_list) {
    for (const auto& service : method_list.services()) {
      Stats::StatName stat_name_service = stat_name_pool_.add(service.name());

      for (const auto& method_name : service.method_names()) {
        Stats::StatName stat_name_method = stat_name_pool_.add(method_name);
        map_[std::make_tuple(service.name(), method_name)] =
            Grpc::Context::RequestStatNames{stat_name_service, stat_name_method};
      }
    }
  }

  absl::optional<Grpc::Context::RequestStatNames>
  lookup(const Grpc::Common::RequestNames& request_names) const {
    auto it = map_.find(std::make_tuple(request_names.service_, request_names.method_));
    if (it != map_.end()) {
      return it->second;
    }

    return {};
  }

private:
  struct MapHash : absl::Hash<std::tuple<std::string, std::string>>,
                   absl::Hash<std::tuple<absl::string_view, absl::string_view>> {
    using is_transparent = void;
  };

  struct MapEq {
    using is_transparent = void;
    bool operator()(const std::tuple<std::string, std::string>& left,
                    const std::tuple<std::string, std::string>& right) const {
      return left == right;
    }
    bool operator()(const std::tuple<std::string, std::string>& left,
                    const std::tuple<absl::string_view, absl::string_view>& right) const {
      return left == right;
    }
  };
  absl::flat_hash_map<std::tuple<std::string, std::string>, Grpc::Context::RequestStatNames,
                      MapHash, MapEq>
      map_;
  Stats::StatNamePool stat_name_pool_;
};

2020-03-25T00:27:03.1101292Z [ RUN      ] ClusterRefreshManagerTest.Basic
2020-03-25T00:27:03.1101953Z test/extensions/common/redis/cluster_refresh_manager_test.cc:149: Failure
2020-03-25T00:27:03.1102599Z Expected equality of these values:
2020-03-25T00:27:03.1103371Z   cluster_info->redirects_count_
2020-03-25T00:27:03.1103972Z     Which is: 1
2020-03-25T00:27:03.1104438Z   0
2020-03-25T00:27:03.1104863Z Stack trace:
2020-03-25T00:27:03.1105518Z   0x8d129cb: Envoy::Extensions::Common::Redis::ClusterRefreshManagerTest_Basic_Test::TestBody()
2020-03-25T00:27:03.1106736Z   0x1446c39e: testing::internal::HandleSehExceptionsInMethodIfSupported<>()
2020-03-25T00:27:03.1107618Z   0x14418d36: testing::internal::HandleExceptionsInMethodIfSupported<>()
2020-03-25T00:27:03.1108276Z   0x143c2af7: testing::Test::Run()
2020-03-25T00:27:03.1108864Z   0x143c5800: testing::TestInfo::Run()
2020-03-25T00:27:03.1109413Z ... Google Test internal frames ...