Use Slightly Higher Level Types about fuser

[siscia]

Since we are talking about changes to the API, I was working on an API that returns a Result<Something, ErrorCode> instead of using the (I think) awkward Reply API.

[cberner]

Thanks for the suggestion. I think this is a good idea. Although, if I understand correctly it would be a breaking change to the Filesystem API. I don't want to introduce breaking changes unless they're necessary. I'll consider changing this if I make a bigger update to that API though. I'd like to add support for async at some point, and I'm sure that will result in a large change

[wmanley]

I created such newtypes in #119, but they're not yet exposed as public API. I'm working towards that in #136, tracking issue: #138.

[cberner]

Closing due to inactivity, but feel free to re-open if you're still working on this.