added time sync #7 and timestamping of message

client/client/lib/espnow/src/espnow.cpp

 #include <esp_now.h>
 #include <Preferences.h>
+#include <ESP32Time.h>
 #include "WiFi.h"
 #include "espnow.hpp"
 
@@ -7,6 +8,7 @@ uint8_t BROADCAST_MAC[] = {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}; // leaving this
 bool host_defined = false;
 esp_now_peer_info_t hostInfo;
 Preferences preferences;
+ESP32Time rtc(7200);
 
 void on_data_sent(const uint8_t *mac_addr, esp_now_send_status_t status){
     // go to sleep
@@ -23,6 +25,7 @@ void on_data_recv(const uint8_t *mac, const uint8_t *incomingData, int len){
     }// host change shouldn't be an issue
     preferences.end();
     // sync time
+    rtc.setTime(new_config.time_millis); // see https://www.esp32.com/viewtopic.php?t=9965, maybe this needs an offset
 }
 
 
@@ -69,6 +72,7 @@ void Message::add_data(float value, int identifier){
 
             if(data->timestamp == 0){
                 //add timestamp
+                data->timestamp = rtc.getMillis();
             }
         }