Feature request: PostEvictionCallback

[ruslan528]

In common scenarios developer want to log eviction from cache. This is an important feature to improve observability of application. I propose to add new optional parameter to constructor - delegate (see Microsoft.Extensions.Caching.Memory.PostEvictionDelegate).

[alex-jitbit]

Thanks!

Do you mean one call back for every item, or cache-global?

[ruslan528]

I think that "cache-global" implementation will be enough. That universal "PostEvictionDelegate" will receive evicted item - so we will have ability to log his key and value.