Record and replay ROS 2 topic, service and action data with rosbag2

Documented steps

1. Source ROS 2 in every terminal, then start the demo system: terminal 1 `ros2 run turtlesim turtlesim_node`, terminal 2 `ros2 run turtlesim turtle_teleop_key`.
2. Create and enter a directory for recordings - the bag is written into the directory you run the command from: `mkdir bag_files && cd bag_files`.
3. List topics: `ros2 topic list` - expect /parameter_events, /rosout, /turtle1/cmd_vel, /turtle1/color_sensor, /turtle1/pose.
4. Optionally confirm data is flowing: `ros2 topic echo /turtle1/cmd_vel` while driving the turtle from the teleop terminal.
5. Record one topic: `ros2 bag record --topics /turtle1/cmd_vel`. The bag directory is named rosbag2_<date>-<time>. Ctrl-C to stop.
6. Record several topics into a named bag: `ros2 bag record -o subset --topics /turtle1/cmd_vel /turtle1/pose`. Use `-a` to record every topic instead.
7. Split long recordings by duration or size: `ros2 bag record -o subset_split -d 5 --topics /turtle1/cmd_vel /turtle1/pose` (`-d <seconds>` or `-b <bytes>`).
8. Inspect a recording: `ros2 bag info subset` - shows storage id, ROS distro, duration, message counts and per-topic type/serialization format.
9. Replay (stop the teleop first): `ros2 bag play subset`. SPACE pauses/resumes; arrow keys change playback rate.
10. Play multiple bags together in original message order: `ros2 bag play -i subset_cmd_vel -i subset_pose`, optionally with `--message-order {received,sent}` (default received).
11. To record service traffic, enable Service Introspection on the nodes, then `ros2 bag record --service <names>` or `--all-services`; replay with `ros2 bag play --publish-service-requests <bag>`.
12. To record action traffic, enable Action Introspection, then `ros2 bag record --action <names>` or `--all-actions`; replay with `ros2 bag play --send-actions-as-client <bag>`.
13. Official doc: https://docs.ros.org/en/lyrical/Tutorials/Beginner-CLI-Tools/Recording-And-Playing-Back-Data/Recording-And-Playing-Back-Data.html