watch_key

Description:

public unowned AccountWatch watch_key (string key, AccountNotifyCb callback)

Installs a watch on key: callback will be invoked whenever the value of key changes (or the key is removed).

this	the Account.
key	the name of the key to watch.
callback	a AccountNotifyCb callback to be called.
user_data	pointer to user data, to be passed to `callback`.

a AccountWatch, which can then be used to remove this watch.