feat req: Partial Serialization

[Nul-led]

Partial serialization and deserialization (eg through a mutable reference) would allow for further space / bandwidth optimizations by giving users the option of rolling out their own fieldwise change detection.

The exists an implementation of this behavior in serde as a reference.

https://docs.rs/serde-partial/latest/serde_partial/

[finnbear]

For change detection, consider wrapping in https://crates.io/crates/diff-struct (we might make our own diffing library compatible with bitcode derive).

It would also be interesting to know if serde_partial is compatible with existing bitcode::{serialize, deserialize}.