Apachai.OAuth.PercentEncode C# (CSharp) Method

        public static string PercentEncode(string s)
        {
            var sb = new StringBuilder ();

            foreach (byte c in Encoding.UTF8.GetBytes (s)){
                if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '-' || c == '_' || c == '.' || c == '~')
                    sb.Append ((char) c);
                else {
                    sb.AppendFormat ("%{0:X2}", c);
                }
            }
            return sb.ToString ();
        }