message: Snackbar: onActionClick is private and readonly now
diff: @@ -107,7 +107,7 @@ class Snackbar extends PureComponent<SnackbarProps, SnackbarState> {
  clearTimeout(this.closeTimeout);
  };
  - onActionClick = (e: MouseEvent) => {
  + private readonly onActionClick = (e: MouseEvent) => {
  this.close();
  if (this.props.action && typeof this.props.onActionClick === 'function') {
  