* timer: restructure feature flags
* update timer tests
* Add `async-traits` to CI
This also disables a buggy `threadpool` test. This test should be fixed in the future.
Refs #1225
This patch introduces `Timeout`. This new type allows setting a timeout
both using a duration and an instant. Given this overlap with
`Deadline`, `Deadline` is deprecated.
In addition to supporting future timeouts, the `Timeout` combinator is
able to provide timeout functionality to streams. It does this by
applying a duration based timeout to each item being yielded.
The main reason for introducing `Timeout` is that a deadline approach
does not work with streams. Since `Timeout` needed to be introduced
anyway, keeping `Deadline` around does not make sense.
Carl Lerche