#include <math.h>
#include <algorithm>
+#include <chrono>
#include <locale>
#include <sstream>
using namespace std;
+using namespace std::chrono;
Metrics global_metrics;
+double get_timestamp_for_metrics()
+{
+ return duration<double>(system_clock::now().time_since_epoch()).count();
+}
+
namespace {
string serialize_name(const string &name, const vector<pair<string, string>> &labels)