I have written a node that is modeled after point_cloud_converter to convert
between two related types. Depending on the sequence in which I start my
nodes, some of the message callbacks get called or are ignored.

I have attached a (different but simple) python node that shows the problem.

If I run:  python cyclic.py in:=in1
followed by: python cyclic.py out:=in1 in:=out
then both the callbacks get called.

However, when I reverse the order in which I launch the nodes:
python cyclic.py out:=in1 in:=out

followed by: python cyclic.py in:=in1
the callback in only the second node is called.

What I am doing incorrectly? Is there some handshaking code that I am not
using?

Advait