GBP-layer group node for the
[Group Protocol Stack](https://github.com/F000NKKK/Group-Protocol-Stack).
This is the IP-like substrate that the three sub-protocol crates
(`gtp-protocol`, `gap-protocol`, `gsp-protocol`) build on. It owns the
framing, AEAD, replay window, FSM and control plane.
Licensed under [Apache License, Version 2.0](../../../LICENSE).