Add a helper to simplify passing smd ss rx traffic into the local
smd participants, excluding the rx that received it externally to
avoid looping.
Make the smd readme clearer with three diagrams and more explanation
of how the ss proxying works.
- Add low level system message distibution framework
- Add support for local Secure Streams to participate using _lws_smd streamtype
- Add apit test and minimal example
- Add SS proxy support for _lws_smd
See minimal-secure-streams-smd README.md
