Reference to discussing "rostopic command for ROS2"

ROS topic commands are very useful for simple performance tests such as hz/delay/bw, but those tools are not supported in ros2 topic right now, if there is no body work on there. I would like to contribute to port ROS topic(hz/delay/bw) to ROS2.

Todo list:

• [ ros2 topic hz] (Enable ros2tpoic hz command #133)
• [ ros2 topic delay] (Enable ros2topic delay command #139)
• [ ros2 topic bw] (Port rostopic bw #190)