dispose (#276)

Author: bitfaster

BitFaster.Caching/Lfu/ConcurrentLfu.cs

@@ -210,6 +210,8 @@ public V GetOrAdd(K key, Func<K, V> valueFactory)
                     AfterWrite(node);
                     return node.Value;
                 }
+
+                Disposer<V>.Dispose(node.Value);
             }
         }
 
@@ -229,6 +231,8 @@ public async ValueTask<V> GetOrAddAsync(K key, Func<K, Task<V>> valueFactory)
                     AfterWrite(node);
                     return node.Value;
                 }
+
+                Disposer<V>.Dispose(node.Value);
             }
         }