Varint enum tags and lengths

[ZoeyR]

Resolves #319

This is a continuation of PR #271 based on feedback in that PR. The primary change is to use a config option instead of a feature in order to use varint sequence lengths and discriminants.

[ZoeyR]

@dtolnay can I get a review of this?

[dtolnay]

Hi @ZoeyR, I think #294 (review) applies here. I think this is useful but it would be better to pursue in a different library.

[ZoeyR]

@dtolnay I thought based on #157 (which you opened) and #271 (which you seemed agreeable towards) that this PR would be a good fit for the library. It doesn't offer all of the configuration of #294 because IMO the amount of config in #294 is a bit of a footgun.

[strega-nil]

This needs some changes, but otherwise, is a really good changeset.

[strega-nil]

Add a newline here

[codecov-io]

Codecov Report

Merging #306 into master will decrease coverage by 5.33%.
The diff coverage is 51.50%.

@@            Coverage Diff             @@
##           master     #306      +/-   ##
==========================================
- Coverage   63.18%   57.84%   -5.34%     
==========================================
  Files           7        7              
  Lines         622      733     +111     
==========================================
+ Hits          393      424      +31     
- Misses        229      309      +80     

Impacted Files	Coverage Δ
src/config.rs	20.51% <19.62%> (-1.08%)	⬇️
src/de/mod.rs	77.57% <88.09%> (+0.43%)	⬆️
src/ser/mod.rs	78.87% <88.23%> (+2.59%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a8ce052...e9f9188. Read the comment docs.

[fabricedesre]

Hi! Is there anything blocking that to land?

[strega-nil]

@fabricedesre COVID, but also I'd like to add varint encoding forall integers.

[Zaxar163]

When this PR will be accepted?

[ZoeyR]

@Zaxar163 once we've worked out the kinks with signed number varints.

[alanjds]

Hi. When will this be released as a crate?

[ZoeyR]

Hi @alanjds this was release a few months ago as part of bincode 1.3