I'm not sure if this a bug or a 'feature', but I'm seeing that if I do
something like:

rostopic pub -r 50 /sometopic geometry_msgs/TransformStamped '{header:
auto, child_frame_id: /bla, transform: {translation: {x: 0, y: 0, z:
0}, rotation: {x: 0, y: 0, z: 0, w: 1}}}'

or

rostopic pub -r 50 /sometopic geometry_msgs/TransformStamped '{header:
{stamp: now, frame_id: foo}, child_frame_id: /bla, transform:
{translation: {x: 0, y: 0, z: 0}, rotation: {x: 0, y: 0, z: 0, w:
1}}}'

.. then the header timestamp is populated, but only with a single time
(I guess the time the first message is sent). It would make more sense
to me to have the timestamp change with every message. Is there a
reason it doesn't?

Thanks,
Pat