fix: be specific about returned backing array

[achingbrain]

Since ArrayBuffer and SharedArrayBuffer types diverged, some APIs require Uint8Array<ArrayBuffer> which makes it incompatible with the default Uint8Array (e.g. Uint8Array<ArrayBufferLike>, e.g. Uint8Array<ArrayBuffer | SharedArrayBuffer>) so update the return type of encode to make clear what type of backing buffer is used.

This means that onward code doesn't need to check the backing type.

[rvagg]

Would you mind just limiting this to the json path? Narrowing the various encode paths is a breaking change and I don't think there's a good reason to stop supporting the caller giving a SharedArrayBuffer to write in to, that's perfectly valid today. Since we allocate for the json path we can easily be precise, but where we accept a sink as an input, restricting what you can write to is a step backwards.

I think we might be able to achieve what you want with some generics hackery, make encode() and jsonEncode() be clear about what they return, a Uint8Array<ArrayBuffer> because we're responsible for it, but for encodeInto leave it as an Uint8Array<ArrayBufferLike>. Then we don't lose the flexibility of "just write to my thing please".

[rvagg]

@achingbrain see if #184 does what you want, I think it solves for both situations

[achingbrain]

Fair enough, completely agree on keeping encodeInto permissive, that was an oversight on my part.

#184 looks good to me.