private void IncrementInternalValue(string key, int increment)
        {
            var countValue = (int?)namedCache.Retrieve(key, true) ?? 0;
            var newValue   = countValue + increment;

            if (namedCache.Contains(key))
            {
                namedCache.Update(key, newValue, true);
            }
            else
            {
                namedCache.Insert(key, newValue, infinitePolicy, true, true);

                var metadata = new ObjectMetadata();
                metadata.IndexCollection[KeyPrefixIndex] = keyPrefixInternalIndexValue;

                namedCache.SetMetadata(key, metadata, true);
            }
        }