Reason: Duplicates are not handled correctly. Which causes one of the internal lists (entries) to grow over time until handling the numberous items increases processing overhead and cause a slowdown.
Background: We are pulling a queue using n consumers with zero prefetch for maximum round robin. (Using Failover-Transport.)
Processing a message can take time from split a second to several hours. Prefetching a message would not be good. Nether-the-less this is a good way to do it, we discovered increasing memory usage and slowing down of our "workers".
After a worker processed a task a new call to consumer.Receive(timeout) causes to send a new MessagePull request, which is put into the messageCache using the same id.
(ProcessMessagePull in ConnectionStateTracker)
This causes the grow.
Reason: In LRUCache.this method, the call to entries.Remove uses value and not currentValue.