namespace System
{
    [DefaultMember("Chars")]
    public sealed class String : IEnumerable, IEnumerable<char>, ICloneable, IComparable, IComparable<string?>, IConvertible, IEquatable<string?>, IParsable<string!>, ISpanParsable<string!>
    {
        public static string! Join(char separator, string?[]! value, int startIndex, int count);
    }
}