Allow using tokio's AsyncBufRead

[endor]

I would like to use quick-xml together with tokio's AsyncRead, as I am fetching an object from S3 with rusoto_s3 and that returns a body that implements AsyncRead. This is an attempt at making that happen.

[endor]

The unit tests in unit_tests.rs and test.rs are now working with and without async.

[endor]

Looks like the Deserializer would need to support async as well.

[endor]

I realize that this is not the best solution, because there's a lot of duplication. I'm just not sure how else to do it. I don't have a lot of experience with async code in Rust.

• If we were to for example wrap a sync Reader in some kind of wrapper to make it async, so they could share more code, we would force the user to use a runtime, I guess.
• If we were to split the async part into a separate crate/library than any changes made to one would need to manually be also made to the other.
• Maybe we could share a bit more code if the methods that are sync in the async Reader would be put into a trait or something, but a lot of the methods are async in the async Reader and they cannot be shared.

[endor]

After some feedback, I've changed the design a bit now and introduced an AsyncReader instead of overloading the Reader. This also allows me to leave the Deserializer as is for now and all the tests pass. There's obviously still duplication but it seems like a cleaner abstraction. The doc tests now also work.

[endor]

@tafia Any thoughts on this?

[tafia]

Ouch, it's been really long that this issue is opened, really sorry for that.
I love the idea, I need to get into it a little more and update it with (now released) tokio 1.0. Thank you so much and very sorry for the late answer.

[endor]

I rebased the PR now on current master. Next step is to update tokio. It seems like there's a broken test in master.

[endor]

tokio is updated.

[endor]

I also fixed the one unit test failing in master.

[endor]

ping @tafia

[agentsim]

@tafia Any update on whether or not this can get merged?

[tafia]

Sorry, this is definitely something I consider, I'll have a look in depth today.

[agentsim]

That would be great, thanks! For what it's worth, I've been using this branch and haven't run into any problems.

[itsgreggreg]

Also FWIW, I'm writing an XMPP server and am interested in this functionality so I can switch to async multi-client handling. Happy to help push this along in any capacity. Fix conflicts, tests, etc. Lemme know if I can help!

[tafia]

@itsgreggreg I'd appreciate a rebase, thanks!

[endor]

I caught up on some of the changes that were recently made, but the BufferedInput change takes a bit more work. I might get to it soon.

[garma83]

any updates on this? or tips how to get this to work?

[dralley]

Closing this old PR in favor of #417