Feature: In Memory Cache should support specifying the Max Memory Size #399
Description
InMemoryCache has no built-in way to cap memory usage other than MaxItems. A service that keeps adding entries can grow without bound.
Motivation
Protect long-running processes from out-of-memory failures.
Give operators a predictable upper bound on cache size.
Align with behavior already offered by other cache libraries (see MemoryCacheOptions.SizeLimit)