fix every clippy warning possible, remove io_uring as default feature

this project's codebase is so horrendous, im shocked that no one has ran
clippy at all. it had ~200 total lint warnings, some with performance
issues and unsoundness, and the rest just very ugly codebase. i have sat
down and fixed as many of these as possible and i am exhausted.
i haven't fixed some extremely complex ones, but i brought it down from
~200 to ~30.

i have also removed io_uring as a default feature due to it falling
under the same category as linux eBPF: major kernel attack surface for
minimal performance gains. this also makes it impossible to cross-compile
from macOS to Linux because io_uring does not exist in Darwin land.
there are far better ways to achieve better performance than io_uring on
the codebase level.

Signed-off-by: strawberry <june@girlboss.ceo>

src/service/pdu.rs

@@ -383,10 +383,9 @@ impl PartialEq for PduEvent {
         self.event_id == other.event_id
     }
 }
-#[allow(clippy::non_canonical_partial_ord_impl)]
 impl PartialOrd for PduEvent {
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        self.event_id.partial_cmp(&other.event_id)
+        Some(self.cmp(other))
     }
 }
 impl Ord for PduEvent {