@CheckReturnValue @Nonnull static public String appendTwoHexFromInt(int val,@Nonnull String inString){
  StringBuilder sb=new StringBuilder(inString);
  sb.append(StringUtil.twoHexFromInt(val));
  return sb.toString();
}

@ CheckReturnValue @ Nonnull static public String appendTwoHexFromInt ( int val , @ Nonnull String inString ) { StringBuilder sb = new StringBuilder ( inString ) ; sb . append ( StringUtil . twoHexFromInt ( val ) ) ; return sb . toString ( ) ; }
quickly append an integer to a string as exactly two hexadecimal characters
