Feat/add redis example

[rnelson]

No description provided.

[rnelson]

A lot of stuff broke with this. Most notably, I disabled local cache for the distributed thing forgetting that it's not always the case. We should only disable local cache when there is no IDistributedCache available.

In trying to fix it, I started putting everything in the DI container instead of doing the static instances everywhere. That broke it much further, because I don't have a DI container in the tests.

Need to figure out how to give xUnit a DI container and register things with it.

[rnelson]

Closing PR for the moment. Finishing up some code coverage stuff, then I need to make sure the standalone still works fine then test this branch with Aspire/Redis/Docker again.

[rnelson]

A lot of the library was rewritten, properly setting it up using dependency injection (as is the norm for ASP.NET Core, and how it was already built to be added). This fixed a few issues that cropped up in unit tests previously and greatly simplified a lot of stuff.

A package is being generated, a readme is written, public bits are mostly/all documented, local memory cache works great, unit tests all pass, and the library has 100% unit test code coverage.

The only remaining item is fixing a bug with the Redis example. When an IDistributedCache is available and pointing at a Redis instance, Redis is properly updated by the middleware. Unfortunately, the IMemoryCache is used and never refreshed from the distributed cache. What this results in is a first API using the shared cache will count requests and write that to Redis, but when the second API goes to do something it will check its memory cache (creating the entry if needed), use a value of 0, then write that to Redis. Requests to the two APIs just go back and forth overwriting one another, with each reading its in-memory cache first.

The in-memory cache can be disabled, but doing so makes non-distributed uses completely break because they have nowhere to store the data.

• There is no Redis in unit tests as the middleware never knows Redis is involved.

I've tried having CacheHelper (the one bit of code that directly works with the HybridCache) get an IDistributedCache and check if it's null, enabling/disabling local memory cache accordingly, but the unit tests break horribly because the container expects a non-null instance for that to then be found.

I've asked on Bluesky (no responses yet) and dug through a bunch of the HybridCache code, including DefaultHybridCache.cs. I may just be missing something obvious. Quitting for the night and coming back with fresh eyes tomorrow.

cc @rbenoit this is the one and only thing left at this point, if you're free to work on it tomorrow go forth