Why doesn't std_msgs::Float32MultiArray have a Header field?
Some messages (e.g., sensor_msgs::PointCloud2) have Header fields, while many others don't.
In particular, why don't float32 multiarrays (or any other std_msg/ messages) have header fields? Why was the decision made to only selectively provide header fields. How am I supposed to track the timing of messages without header fields, since the header contains the timestamp?