- `CacheControl.FlushCaches`
- `Querier.Query`
- `Resolver.Resolve`
Besides all the API churn, this leads to `ParallelBestResolver`,
`StrictResolver` and `UpstreamResolver` simplification: timeouts only
need to be setup in one place, `UpstreamResolver`.
We also benefit from using HTTP request contexts, so if the client
closes the connection we stop processing on our side.
* added util for handling EDNS0 options
* disable caching if the request contains a netmask size greater than 1
* added config section for ECS handling and validation for it
*added ecs_resolver for enhancing and cleaning subnet and client IP information