docs: public static Object readUrl(Context cx, Scriptable thisObj, Object[] args,
                                   Function funObj)
          throws IOException
      {
          if (args.length == 0) {
              throw reportRuntimeError("msg.shell.readUrl.bad.args");
          }
          String url = ScriptRuntime.toString(args[0]);
          String charCoding = null;
          if (args.length >= 2) {
              charCoding = ScriptRuntime.toString(args[1]);
          }
  
          return readUrl(url, charCoding, false);
      }