code: @NonNull
    @SuppressWarnings("WeakerAccess")
    public SnackbarWrapper setIcon(Drawable icon) {
      messageView.setCompoundDrawablesWithIntrinsicBounds(icon, null, null, null);
      return this;
    }
docs: Set the icon at the start of the Snackbar. If there is no icon it will be added, or if there is then it will be
  replaced.
  
  @param icon The icon to display.
  @return This instance.