code: protected function stringize(array &$arguments)
      {
          array_walk($arguments, function (&$value) {
              if (is_object($value)) {
                  $value = get_class($value);
              } elseif (is_scalar($value)) {
                  $value = (string) $value;
              } else {
                  $value = json_encode($value, 0);
              }
          });
          return $this;
      }
docs: Convert any non-string item in the arguments to string
  
  @param array &$arguments
  @return $this
  @access protected
  @since  2.0.10 modified to use json_encode