private void RemoveFromCache(MemoryCacheEntry entry, CacheEntryRemovedReason reason, bool delayRelease = false)
        {
            // release outside of lock
            if (entry != null)
            {
                if (entry.InExpires())
                {
                    _expires.Remove(entry);
                }

                if (entry.InUsage())
                {
                    _usage.Remove(entry);
                }

                Dbg.Assert(entry.State == EntryState.RemovingFromCache, "entry.State = EntryState.RemovingFromCache");

                entry.State = EntryState.RemovedFromCache;
                if (!delayRelease)
                {
                    entry.Release(_cache, reason);
                }
                if (_perfCounters != null)
                {
                    _perfCounters.Decrement(PerfCounterName.Entries);
                    _perfCounters.Increment(PerfCounterName.Turnover);
                }
            }
        }