namespace System
{
    public abstract class StringComparer : IComparer<string?>, IEqualityComparer<string?>, IComparer, IEqualityComparer
    {
        public static bool IsWellKnownCultureAwareComparer(IEqualityComparer<string?>? comparer, [NotNullWhen(true)] out CompareInfo? compareInfo, out CompareOptions compareOptions);
    }
}