Allow first feedback sooner than 1 second / allow feedback for markers created during paused sim_time

[eschluntz]

Hello!

I would like to be able to apply feedback to a marker sooner than 1 second after it has been created. This is currently blocked by

# if two callers try to modify the same marker, reject (timeout= 1 sec)
if marker_context.last_client_id != feedback.client_id \
    and (rospy.Time.now() - marker_context.last_feedback).to_sec() < 1.0:
        rospy.logdebug("Rejecting feedback for ...

because of how marker_context.last_feedback and marker_context.last_client_id are initialized.

This also means that any markers created while sim_time is paused will never get feedback until sim_time is unpaused. My use case here is pausing a bag file and using interactive markers to annotate some data.

If I understand correctly, this could be fixed by initializing market_context.last_feedback to zero, or explicitly checking for last_client_id = ""

Happy to create a PR if you're supportive of this change!

Best,

• Erik