URLError Safe to Use In URLSession response?

Hello,

Foundation declares a URLError struct with a comment saying that URLError describes errors in the URL error domain:

/// Describes errors in the URL error domain.
public struct URLError {
     /// The type of an error code.
    @objc public enum Code : Int {
        case unknown
        case ...
     }
}

In the response of URLSession.dataTask(with url: URL, completionHandler: (Data?, URLResponse?, Error?) ),

casting the Error to a URLError succeeds.

Does URLSession now always return a URLError if an error occurred, or is it only in some cases?

If so, are there plans to update the signatures of the URLSession.dataTask methods to the URLError type?

Thanks!