Potential fixes for 3 code quality findings

src/policy/lru.rs

@@ -228,7 +228,7 @@
 //! };
 //! use std::sync::Arc;
 //!
-//! // Single-threaded usage
+//! // Single-threaded usage (non-concurrent)
 //! let mut cache: LruCore<u32, String> = LruCore::new(100);
 //! cache.insert(1, Arc::new("page_data".to_string()));
 //!
@@ -241,6 +241,17 @@
 //!     println!("Peeked: {}", value);  // returns Arc<String>
 //! }
 //!
+//! // Multi-threaded usage with thread-safe wrapper
+//! let cache: ConcurrentLruCache<u32, String> = ConcurrentLruCache::new(100);
+//!
+//! // Clone the handle and send to other threads; internal access is synchronized.
+//! let cache_clone = cache.clone();
+//! cache_clone.insert(2, Arc::new("other_page".to_string()));
+//!
+//! if let Some(value) = cache_clone.get(&2) {
+//!     println!("Concurrent got: {}", value);  // safe across threads
+//! }
+//!
 //! // Evict least recently used
 //! if let Some((key, value)) = cache.pop_lru() {
 //!     println!("Evicted key={}, value={}", key, value);
@@ -312,7 +323,7 @@
 use crate::metrics::snapshot::LruMetricsSnapshot;
 #[cfg(feature = "metrics")]
 use crate::metrics::traits::{
     CoreMetricsRecorder, LruMetricsReadRecorder, LruMetricsRecorder, MetricsSnapshotProvider,
 };
 use crate::prelude::ReadOnlyCache;
 use crate::traits::{CoreCache, LruCacheTrait, MutableCache};
@@ -626,11 +637,11 @@
     #[inline]
     pub fn peek(&self, key: &K) -> Option<Arc<V>> {
         #[cfg(feature = "metrics")]
-        (&self.metrics).record_peek_lru_call();
+        self.metrics.record_peek_lru_call();
 
         if let Some(&id) = self.map.get(key) {
             #[cfg(feature = "metrics")]
-            (&self.metrics).record_peek_lru_found();
+            self.metrics.record_peek_lru_found();
             let node = self.arena.get(id).expect("peek: stale SlotId");
             return Some(Arc::clone(&node.value));
         }
@@ -680,13 +691,13 @@
     #[inline]
     fn peek_lru(&self) -> Option<(&K, &Arc<V>)> {
         #[cfg(feature = "metrics")]
-        (&self.metrics).record_peek_lru_call();
+        self.metrics.record_peek_lru_call();
 
         let tail_id = self.tail?;
         let node = self.arena.get(tail_id)?;
 
         #[cfg(feature = "metrics")]
-        (&self.metrics).record_peek_lru_found();
+        self.metrics.record_peek_lru_found();
 
         Some((&node.key, &node.value))
     }
@@ -714,19 +725,19 @@
 
     fn recency_rank(&self, key: &K) -> Option<usize> {
         #[cfg(feature = "metrics")]
-        (&self.metrics).record_recency_rank_call();
+        self.metrics.record_recency_rank_call();
 
         let &target_id = self.map.get(key)?;
         let mut rank = 0usize;
         let mut current = self.head;
 
         while let Some(id) = current {
             #[cfg(feature = "metrics")]
-            (&self.metrics).record_recency_rank_scan_step();
+            self.metrics.record_recency_rank_scan_step();
 
             if id == target_id {
                 #[cfg(feature = "metrics")]
-                (&self.metrics).record_recency_rank_found();
+                self.metrics.record_recency_rank_found();
                 return Some(rank);
             }
             rank += 1;