default CharSeq join(CharSequence delimiter,CharSequence prefix,CharSequence suffix){
  StringBuilder stringBuilder=new StringBuilder(prefix);
  forEach(null);
  stringBuilder.append(suffix);
  return CharSeq.of(stringBuilder.toString());
}

default CharSeq join ( CharSequence delimiter , CharSequence prefix , CharSequence suffix ) { StringBuilder stringBuilder = new StringBuilder ( prefix ) ; forEach ( null ) ; stringBuilder . append ( suffix ) ; return CharSeq . of ( stringBuilder . toString ( ) ) ; }
convert all elements into string , and connect each string together to a single string , following the same order of the seq . insert a delimiter at each connection point . add prefix and suffix to the final result .
