docs: public String getHexByteString(CharSequence prefix, CharSequence separator, CharSequence suffix) throws IOException {
          byte data[] = getBytes();
          StringBuilder sb = new StringBuilder();
          for (int i = 0; i < data.length; i++)
          {
              if(i > 0) sb.append(separator);
              int v = data[i] & 0xff;
              if(prefix != null) sb.append(prefix);
              sb.append(hexArray[v >> 4]);
              sb.append(hexArray[v & 0xf]);
              if(suffix != null) sb.append(suffix);
          }
          return sb.toString();
      }