nits

Author: patrick-ogrady

consensus/src/marshal/coding/marshaled.rs

@@ -569,7 +569,6 @@ where
                 let parent_fetch_duration = proposal_parent_fetch_duration.start(&runtime_context);
                 let parent = select! {
                     _ = tx.closed() => {
-                        parent_fetch_duration.discard();
                         debug!(reason = "consensus dropped receiver", "skipping proposal");
                         return;
                     },
@@ -623,7 +622,6 @@ where
                 let build_duration = build_duration.start(&runtime_context);
                 let built_block = select! {
                     _ = tx.closed() => {
-                        build_duration.discard();
                         debug!(reason = "consensus dropped receiver", "skipping proposal");
                         return;
                     },

consensus/src/marshal/standard/deferred.rs

@@ -395,7 +395,6 @@ where
                 let build_duration = build_duration.start(&runtime_context);
                 let built_block = select! {
                     _ = tx.closed() => {
-                        build_duration.discard();
                         debug!(reason = "consensus dropped receiver", "skipping proposal");
                         return;
                     },

consensus/src/marshal/standard/inline.rs

@@ -324,7 +324,6 @@ where
                 let build_duration = build_duration.start(&runtime_context);
                 let built_block = select! {
                     _ = tx.closed() => {
-                        build_duration.discard();
                         debug!(reason = "consensus dropped receiver", "skipping proposal");
                         return;
                     },

resolver/src/p2p/engine.rs

@@ -259,7 +259,7 @@ impl<
                         let mut guard = self.metrics.cancel.guard(Status::Dropped);
                         if self.fetcher.cancel(&key) {
                             guard.set(Status::Success);
-                            self.fetch_timers.remove(&key).unwrap().discard(); // must exist
+                            let _ = self.fetch_timers.remove(&key).expect("must exist");
                             self.consumer.failed(key.clone(), ()).await;
                         }
                     }

runtime/src/telemetry/metrics/histogram.rs

@@ -91,9 +91,8 @@ pub struct Timed {
 /// A sampled histogram observation.
 ///
 /// This token is explicit: dropping it records nothing. Call [`Started::observe_now`] or
-/// [`Started::observe_at`] to record a duration, or [`Started::discard`] when the timing should
-/// be ignored (for example on a fast-path cancellation).
-#[must_use = "call observe_now/observe_at to record the timing, or discard it explicitly"]
+/// [`Started::observe_at`] to record a duration.
+#[must_use = "call observe_now/observe_at to record the timing, or drop it to skip recording"]
 pub struct Started {
     /// The histogram to record durations in.
     histogram: Histogram,
@@ -152,8 +151,6 @@ impl Timed {
         let result = f();
         if result.is_some() {
             started.observe_now(clock);
-        } else {
-            started.discard();
         }
         result
     }
@@ -174,7 +171,4 @@ impl Started {
     pub fn observe_at(self, end: SystemTime) {
         self.histogram.observe_between(self.start, end);
     }
-
-    /// Discard the observation without recording it.
-    pub fn discard(self) {}
 }