fc7f63f641
We've adopted `tracing` for diagnostics, but currently, it is just being used as a drop-in replacement for the `log` crate. Ideally, we would want to start emitting more structured diagnostics, using `tracing`'s `Span`s and structured key-value fields. A lot of the logging in `h2` is already written in a style that imitates the formatting of structured key-value logs, but as textual log messages. Migrating the logs to structured `tracing` events therefore is pretty easy to do. I've also started adding spans, mostly in the read path. Finally, I've updated the tests to use `tracing` rather than `env_logger`. The tracing setup happens in a macro, so that a span for each test with the test's name can be generated and entered. This will make the test output easier to read if multiple tests are run concurrently with `--nocapture`. Signed-off-by: Eliza Weisman <eliza@buoyant.io>
h2 test support
This crate includes utilities for writing h2 tests. This is broken up into a
separate crate because it requires the unstable feature flag and to enable
tower-h2 to use the same helpers.