replay: use lockstep scheduler

src/modules/replay/Replay.hpp

@@ -206,9 +206,18 @@ protected:
 	 */
 	bool nextDataMessage(std::ifstream &file, Subscription &subscription, int msg_id);
 
+	virtual uint64_t getTimestampOffset()
+	{
+		//we update the timestamps from the file by a constant offset to match
+		//the current replay time
+		return _replay_start_time - _file_start_time;
+	}
+
 	std::vector<Subscription *> _subscriptions;
 	std::vector<uint8_t> _read_buffer;
 
+	float _speed_factor{1.f}; ///< from PX4_SIM_SPEED_FACTOR env variable (set to 0 to avoid usleep = unlimited rate)
+
 private:
 	std::set<std::string> _overridden_params;
 	std::map<std::string, std::string> _file_formats; ///< all formats we read from the file
@@ -222,6 +231,8 @@ private:
 
 	int64_t _read_until_file_position = 1ULL << 60; ///< read limit if log contains appended data
 
+	float _accumulated_delay{0.f};
+
 	bool readFileHeader(std::ifstream &file);
 
 	/**