changed
Description:
Emitted when jar changes.
If a cookie has been added, new_cookie will contain the newly-added cookie and old_cookie will be
null. If a cookie has been deleted, old_cookie will contain the to-be-deleted cookie and
new_cookie will be null. If a cookie has been changed, old_cookie will contain its old
value, and new_cookie its new value.
Parameters:
| old_cookie |
the old Cookie value |
| new_cookie |
the new Cookie value |