Can't seem to get it working. Really simple scenario...

```
<cache expires-after="@TimeSpan.FromMinutes(10)">
    @DateTime.Now
</cache>   

```

Running this in VS2017 in IISExpress (same behaviour in IIS 10 too btw) and hitting refresh in the browser (Chrome) just gives me the current time? I'm using .Net Core 2.1. I'm trying it in a partial and a view component and it just doesn't cache. 

I'm not sure what I'm doing wrong.

For the record, I've added..

```
services.AddMemoryCache();

```

to the Startup ConfigureServices method (although according to the documentation (<https://learn.microsoft.com/en-us/aspnet/core/mvc/views/tag-helpers/built-in/cache-tag-helper?view=aspnetcore-2.1>), I shouldn't even need to do this as it is added automatically - it says so right at the bottom).

This is also using Razor pages