Create a callback group to spin on in Python TransformListener

[jacobperron]

Feature request

Feature description

Same as #442, but applied to the Python implementation.

This will make the behavior consistent between languages.

Implementation considerations

It would be nice to emit a warning if the user is relying on the old behavior, but I'm not sure how feasible this is. At the very least, we should add a release note to the Humble release page to highlight the behavior change.

[gezp]

is anyone working for this? if not, i would like to continue this work for python implementation.

[jacobperron]

I just took a brief look, but it doesn't look like the rclpy executor API supports callback groups (please correct me if I'm mistaken). I've opened a ticket upstream https://github.com/ros2/rclpy/issues/850.

[gezp]

but it doesn't look like the rclpy executor API supports callback groups

sorry, i didn't notice that rclpy API is some different of rlcpp before. you are right, we need some features from rlcpy .