Access to the validator's cache needed to be able to selectively flush items from the cache.

[brianpos]

Or alternately support providing the cache to the settings object so that you don't need to maintain an essentially static validator.
My use case is that I have transient profiles that I wish to validate in the service and not retain the extra compiled schemas for the transient profiles.

The CachedResolver has access to clear and invalidate a URL - these are specifically what I would like to be able to do.

The way I used this in the old validator was to provide the following as myroutines source

var inMemResolver = ...; // an in memory resolver that's backed by a simple Dictionary that is populated in the operation
var _dirSource = new DirectorySource(Directory, ... );
var cacheResolver = new CachedResolver(
    new MultiResolver(
       _dbResolver,
        _dirSource,
        ZipSource.CreateValidationSource()
        ));

source = new MultiResolver(inMemResolver, cachedResolver);

Interestingly you copy over the cache in the constructor, even if it already had one too - which would have been a technique to retain the settings, but not the cache - which I'd argue was tied to the resolver...
I assume there was a reason not to put the cache content into an annotation in the SD from the resolver.