Pusher: Caliper plugin: fix timestamp bug

dcdbpusher/sensors/caliper/CaliperSensorGroup.cpp

@@ -160,7 +160,11 @@ void CaliperSensorGroup::read() {
 
         reading_t reading;
         reading.value     = 1;
-        reading.timestamp = std::stoull(timestamp);
+        reading.timestamp = S_TO_NS(std::stoull(timestamp)); //Caliper timestamps are seconds since UNIX epoch
+
+        //a timestamp with a precision of seconds is not unique enough --> append current nanoseconds
+        uint64_t now_ns = getTimestamp() % 1000000000;
+        reading.timestamp += now_ns;
 
         S_Ptr s;
         auto it = _sensorIndex.find(feName);