Add example for bi-directional pub/sub communication

Information

• RTI Product: RTI Connext DDS
• Version: 6.0.0+ / Any

Most of the examples define a single publisher and a single subscriber, each in their own program with a main(). (At least this is the case for c++; I haven't looked at other languages). That means that in each example, data flows in a single direction, across a single topic, from process A to process B.

I am looking for an example of a case where a process can have both a subscriber (e.g. to topic_a), and a publisher (e.g. to topic_b), and a second process that has a mirrored subscriber (topic_b) / publisher (topic_a), and the processes effectively ping-pong back and forth. (I am trying to implement this myself, and I am running into some odd timing issues; I am nearly certain I am missing some best-practice etc.)

Note that there is one example in open pull requests that implements the RequestReply pattern which is helpful, but I am looking for a way to implement bi-directional pub/sub without necessarily using RequestReply, if it is possible.

Apologies if this is a duplicate / already implemented somewhere and I couldn't find it. I searched through closed issues and open PR's and didn't see anything that exactly matched what I am looking for. Thanks!

Start by reviewing the existing C++ publisher/subscriber examples and open pull request #295 for the RequestReply pattern. Compare their setup and timing behavior with the requested two-process, two-topic arrangement. Done means a documented example demonstrates bi-directional pub/sub without requiring RequestReply.