Support for async writer and reader

[cassanof]

Hello, it would be nice to get support for AsyncWrite and AsyncRead, either from Tokio or futures to serialize/deserialize rbxl binary and xml blobs.
I would be happy to do implement it if it's not a problem.

[kennethloeffler]

Hi Federico,

I think rbx_xml and rbx_binary crate features for async reads/writes would be great to have. If you're able, can you describe your use case? This will help justify the addition, and also satisfy my own curiosity 😄

[cassanof]

Hey Kenneth! Sorry, I would like to go into detail but I cannot. Abstractly, it would empower systems that rely on parsing rbx files asynchronously, without blocking.

[Dekkonot]

We're preparing for a new release soon, so it's unlikely that this will make it in before then but I would love to support this. If you want to implement it, feel free but otherwise either me or Ken will get to it soon enough!

[cassanof]

Nice! SGTM. I'll way for the new release :)