This callback is invoked when the value of an account configuration setting
changes. If the callback was installed with ag_account_watch_key() then key
is the name of the configuration setting which changed; if it was installed
with ag_account_watch_dir() then key is the same key prefix that was used
when installing this callback.
This callback is invoked when the value of an account configuration setting changes. If the callback was installed with ag_account_watch_key() then
keyis the name of the configuration setting which changed; if it was installed with ag_account_watch_dir() thenkeyis the same key prefix that was used when installing this callback.