Tower's docs builds are currently failing on `master` because of broken
docs links. These links are broken because they reference modules that
are feature flagged and disabled by default.
In order to build docs successfully, we should build with
`--all-features`. This also means we'll actually build docs for feature
flagged modules --- because we weren't doing that previously, we
actually weren't building most of the docs on CI.
Additionally, I've changed the docs build workflow to build on nightly and
to set `RUSTDOCFLAGS="--cfg docsrs"` so that we can use `doc(cfg)`
attributes when building the Git API docs.
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
CI is currently busted due to [issues with caching `cargo-hack`][1].
Currently, we cache the `cargo-hack` executable to speed up builds by
avoiding the overhead of compiling it from source in every build.
Recently, `cargo-hack` has started publishing binaries on GitHub
Releases. Rather than compiling it on CI and caching it, we can just
download the binary instead. This ought to fix the build.
See also taiki-e/cargo-hack#89 and taiki-e/cargo-hack#91.
[1]: https://github.com/tower-rs/tower/runs/1425940763
This also renames the `Instrument` trait, and related types, to better
reflect what they do. Specifically, the trait is now called
`TrackCompletion`, and `NoInstrument` is called `CompleteOnResponse`.
Also brings back balance example and makes it compile.
