zzzprojects#764 - Set cleanup time prior to enumeration to prevent multiple cleanup hits.

Author: Travis Whidden

src/System.Linq.Dynamic.Core/Parser/ThreadSafeSlidingCache.cs

@@ -66,14 +66,17 @@ private void CleanupIfNeeded()
         {
             if (DateTime.UtcNow - _lastCleanupTime > _cleanupFrequency)
             {
+                // Set here, so we don't have re-entry due to large collection enumeration.
+                _lastCleanupTime = DateTime.UtcNow;
+
                 foreach (var key in _cache.Keys)
                 {
                     if (DateTime.UtcNow > _cache[key].ExpirationTime)
                     {
                         _cache.TryRemove(key, out _);
                     }
                 }
-                _lastCleanupTime = DateTime.UtcNow;
+                
             }
         }
     }