I would love to see (er, work on) a middleware option that used the 'cereal' serializer and ZeroMQ. Is this feasible to implement with the present middleware interface? I looked through the old design document on middleware, but it didn't seem to explain the present interface. Have we any current docs for writing middleware?
I like the 'cereal' approach because it would negate the need for an intermediate message copy before serialization. I also like the capnproto project; however, it wasn't obvious to me how that could be used without the extra copy before serialization.
[Discourse.ros.org] [Next Generation ROS] ZeroMQ middleware -- is it still possible?
This should still be possible. External developers have e.g. implemented the rmw interface using OPC UA. Sadly there is no additional documentation on how to write a custom rmw implementation. The "best" way is to read through the API docs of the interface as well as the existing implementations.