word wrap for monogame

wordwrap.cs

        public static string Wrap(string s, int width, Func<string, int> widthMeasure)
        {
            StringBuilder builder = new StringBuilder(s.Length);
            var text = s.AsSpan();
            int start = 0;
            int len = 0;

            for (int i = 0; i < text.Length; i++) {
                if (text[i] == ' ')
                {
                    if (widthMeasure(text.Slice(start, i-start).ToString()) <= width)
                    {                        
                       len = i - start;                        
                    }
                    else
                    {
                        builder.AppendLine(text.Slice(start,len).ToString());                        
                        start = i;
                        len = 0;
                    }
                } 
            }
            builder.AppendLine(text.Slice(start).ToString());
                                            
            return builder.ToString();
            
        }