title: Eviction Policy for .NET Core unitless fixed size In-memory cache
body: <p>I have declare a FixedSizeMemoryCache singleton in my application.</p>
  <pre><code>    public class FixedSizeMemoryCache
      {
          public MemoryCache Cache { get; private set; }
  
          public FixedSizeMemoryCache()
          {
              Cache = new MemoryCache(new MemoryCacheOptions
              {
                  SizeLimit = 3
              });
          }
      }
  </code></pre>
  <p>I am unable to find out the eviction policy, should the memory size exceed the total size limit. Is there a default compaction happening to check say if the size exceed 75%, compaction will happen in the order as specified in this <a href="https://docs.microsoft.com/en-us/aspnet/core/performance/caching/memory?view=aspnetcore-5.0#memorycachecompact" rel="nofollow noreferrer">link</a>?</p>