How to Trim whitespace from a String in C#

        /// <summary>Trim the ToString() of the object; returning null if null, empty, or whitespace.</summary>
        /// <param name="self"></param>
        /// <returns></returns>
        [DebuggerStepThrough]
        [CanBeNull]
        [Pure]
        public static String? Trimmed<T>( [CanBeNull] this T self ) =>
            self switch {
                null => default( String? ),
                String s => s.Trim().NullIfEmpty(),
                var _ => self.ToString()?.Trim().NullIfEmpty()
            };