In many cases where iocaine was using `unwrap()`, handle it gracefully,
and return a `Result` instead.
Signed-off-by: Gergely Nagy <me@gergo.csillger.hu>
Previously, metrics were behind a feature flag (which was enabled by
default), now it's always available, but still disabled by default.
Signed-off-by: Gergely Nagy <me@gergo.csillger.hu>
These are quite... simple, and cover little, but it's more than nothing!
While there, enable tests in the Nix package, so they're run in CI too.
Signed-off-by: Gergely Nagy <me@gergo.csillger.hu>
