Behavior of MemoryCache.GetValues did not match with dotnet API doc

[t-bzhan]

From the dotnet API doc, the behavior of MemoryCache.GetValues should be:

If a cache entry that is represented by the keys does not exist, the corresponding value for the returned object in the dictionary is set to null. Therefore, the returned dictionary always has the same number of items as the number of elements in keys.

However the actual behavior is that only those key value pairs stored in MemoryCache are returned.

I test the behavior with System.Runtime.Caching 4.7.0 in dotnet core, but the problem should exist for all versions.

[Entropy0]

The behaviour is (arguably) even worse if none of the specified keys exist in the MemoryCache, since then the return value will actually be null instead of the documented dictionary containing all the requested keys.

Are there any plans on fixing this or at least documenting the actual behaviour?