Centralize lifecycle state updates and fix systemd running status (#2567)

crates/io-core/src/timeout_wrapper.rs

@@ -342,11 +342,7 @@ impl TimeoutStats {
     pub fn avg_wait_time(&self) -> Duration {
         let total = self.total_wait_time_ns.load(Ordering::Relaxed);
         let count = self.total_operations.load(Ordering::Relaxed);
-        if count == 0 {
-            Duration::ZERO
-        } else {
-            Duration::from_nanos(total / count)
-        }
+        total.checked_div(count).map(Duration::from_nanos).unwrap_or(Duration::ZERO)
     }
 
     /// Reset statistics.