How to set IActionResult in .NET Standard Library?

I am currently creating a .NET Standard 2.0 library to handle caching with a filter. In my IAsyncActionFilter, when the value is found in cache, I want to short-circuit the flow by setting context.Result, which is an IActionResult. But, I cannot find a nuget package which gives me access to something like Ok(testObject) or OkObjectResult to set the context.Result to.

How can I set the context.Result in a .NET Standard library?