MessagePack is a computer data interchange format. It is a binary form for representing simple data structures like arrays and associative arrays. MessagePack aims to be as compact and simple as possible.
For more information please visit the source repo here: https://github.com/msgpack/msgpack-c
For some reason the sbuf implementation of mutable buffers inside msgpack-c makes the ESP32 crash.
When packing, use the provided msgpack_mbuf_write callback to write into an mbuf instead.