Postcard

A (TODO), no_std, serde compatible message library for Rust.

Design plans

1. usizes are varints
2. enum variants are usizes
3. variable length data, like strings and vecs, are prefixed by their length as a varint/usize, e.g. "hello" is [5, h, e, l, l, o]
4. heapless data structures are used as the first class serialization/deserialization target.
5. there will be a std feature that allows you to either auto-convert from heapless to non-heapless, or jump directly to that, whatever is easier