Password sync plugin, and questions about plugin criticality

[Ken Hornstein]

>First, do you want failure to synchronize to lead to failure to change
>the password?  But you can't guarantee that password change and
>synchronization happen atomically, methinks.  So I'd say, change the
>password, then synchronize to all sinks; ignore (but log!) failures.
>Given such semantics no stacking seems necessary: just call all the
>plug-ins in order, or even concurrently.

It depends on who you talk to; some people are happy with it not
syncing externally; some people absolutely do NOT want the password
change to succeed, and they want the user to get an error message.
Hence the reason for the two functions.

--Ken