From bca1592dfbca2c6e9dfae3b63096a8fc9642e531 Mon Sep 17 00:00:00 2001
From: David Herberth <github@dav1d.de>
Date: Wed, 24 Apr 2024 22:57:25 +0200
Subject: [PATCH] Annotate metric types with must_use

---
 metrics/src/handles.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/metrics/src/handles.rs b/metrics/src/handles.rs
index 490e4df3..33dc62d2 100644
--- a/metrics/src/handles.rs
+++ b/metrics/src/handles.rs
@@ -40,18 +40,21 @@ pub trait HistogramFn {
 
 /// A counter.
 #[derive(Clone)]
+#[must_use = "counters do nothing unless you use them"]
 pub struct Counter {
     inner: Option<Arc<dyn CounterFn + Send + Sync>>,
 }
 
 /// A gauge.
 #[derive(Clone)]
+#[must_use = "gauges do nothing unless you use them"]
 pub struct Gauge {
     inner: Option<Arc<dyn GaugeFn + Send + Sync>>,
 }
 
 /// A histogram.
 #[derive(Clone)]
+#[must_use = "histograms do nothing unless you use them"]
 pub struct Histogram {
     inner: Option<Arc<dyn HistogramFn + Send + Sync>>,
 }