public final ByteArrayBuilder append(StringBuilder stringBuilder,Charset charset) throws UnsupportedEncodingException {
  return append(stringBuilder.toString(),charset);
}

public final ByteArrayBuilder append ( StringBuilder stringBuilder , Charset charset ) throws UnsupportedEncodingException { return append ( stringBuilder . toString ( ) , charset ) ; }
convenience method for append ( byte [ ] ) combined with a string of specified charset
