Playback breakpoints

[jtbandes]

Currently the app provides no way to "find" instances of messages on a certain topic other than by seeking back/forward until the desired message is displayed. If the messages on the desired topic are very high-frequency (such as /tf) it can be very difficult to find and display the desired message in the app.

The app could support a "breakpoints" feature where playback would automatically stop when some kind of event occurs. Such an event could be:

• A certain receiveTime is reached (this could be used to implement forward/back arrow keys as per foxglove/studio#2270)
• A message is received on a certain topic
• A message is received on a certain topic matching a user-defined predicate (e.g. header.frame_id="parent" AND child_frame_id="child")

See also: https://github.com/orgs/foxglove/discussions/885#discussion-5903400

[sachitv]

It would be great if it was possible to somehow expand the timeline view with messages on a per topic basis similar to what rerun does:

Thereafter provide a shortcut keystroke for both:

1. Go to the next time for the selected topic
2. Go to the next time for the log