$ ros2 bag record --storage mcap --output fixture_bag --use-sim-time --topics /bag_demo/point --disable-keyboard-controls
RECORDED: six supplied PointStamped messages; /clock was not recorded
$ ros2 bag info fixture_bag
Storage id:        mcap
Messages:          6
Topic information: Topic: /bag_demo/point | Type: geometry_msgs/msg/PointStamped | Count: 6 | Serialization Format: cdr
STORED: count=6; frames=map; header seconds=[100, 101, 102, 103, 104, 105]
STORED: recorder seconds=[100, 101, 102, 103, 104, 105]
STORED: points=[(0, 0, 0), (0.5, -0.25, 0), (1, -0.5, 0), (1.5, -0.75, 0), (2, -1, 0), (2.5, -1.25, 0)]
$ ros2 bag play fixture_bag --start-paused --disable-keyboard-controls --wait-for-all-acked 3000
FAILURE CASE: count=6; all contents/header stamps unchanged; consumer ROS time=[0, 0, 0, 0, 0, 0]
$ ros2 bag play fixture_bag --start-paused --disable-keyboard-controls --wait-for-all-acked 3000 --clock 20
REPAIR: count=6; all contents/header stamps unchanged; consumer ROS time initializes at 100 seconds and advances
PASS: record, info, stored payloads, both replay counts, preserved stamps, missing-clock diagnosis, and clock repair