Add zstd support

[paolobarbolini]

This PR has been recreated after I accidentally deleted my fork for #1464

Closes #1463

[ozgrakkurt]

This would be very useful indeed

[tafia]

Is there any news / blocking point?

[paolobarbolini]

Is there any news / blocking point?

No blockers on my part. I too wish we could get feedback on this PR, especially considering that lately there has been some progress with zstd on the web https://caniuse.com/zstd

[paolobarbolini]

It looks like Chromium may be close to shipping it ¹. I'd be happy to rebase after the hyper v1 upgrade @seanmonstar.

Footnotes

1. https://chromestatus.com/feature/6186023867908096 ↩

[seanmonstar]

Thanks for pushing on this for so long. I remember looking a while ago, and it seemed to be unhappy on Windows. Assuming it works fine now, I'd be happy to merge.

[paolobarbolini]

Yeah zstd had a Windows issue some time ago, it's been fixed upstream. I think this is ready for merging.

[seanmonstar]

Thanks again! I delayed merging a little bit just in case there was major problems with v0.12 that I'd need to revert or handle. But seems like its pretty smooth now. So this will go out in the next release.