private void maybeClose(@Nullable ArrayList<Entry<K, V>> oldEntries) {
    if (oldEntries != null) {
      for (Entry<K, V> oldEntry : oldEntries) {
        CloseableReference.closeSafely(referenceToClose(oldEntry));
      }
    }
  }
Notifies the client that the cache no longer tracks the given items.

<p>This method invokes the external {@link CloseableReference#close} method, so it must not be
called while holding the <code>this</code> lock.
imagepipeline-base/src/main/java/com/facebook/imagepipeline/cache/LruCountingMemoryCache.java