Macro encoding

macro_rules! encoding {
    ($pub:vis $name:ident, $to_vec:expr, $from_slice:expr) => { ... };
}

The encoding macro can be used to create newtypes that implement a particular encoding for the inner value.

For example, the following line creates a new JSON encoding using serde_json:

extism_convert::encoding!(MyJson, serde_json::to_vec, serde_json::from_slice);

This will create a struct struct MyJson<T>(pub T) and implement ToBytes using serde_json::to_vec and FromBytesOwned using serde_json::from_slice