[Catalyst] Saving redirect URL in flash not sticking through login process

[Eric Berg]

If a user submits a certain form without being logged in, I flash the 
current URL, save the params in the session, and redirect them to the login.

In my Login controller, I look for $c->flash->{redirect_url} and 
redirect them back to that URL.

The problem is that that flash entry is gone after the user submits the 
login form.  I logged out the redirect URL at the beginning of my login 
routine and it comes through the first time, but even if I don't access 
it via the log statement, that redirect_url key is not there in the 
flash when the user submits the login form with their credentials.

I've tried resetting $c->flash->{redirect_url} in the login routine and 
also tried $c->keep_flash( qw( redirect_url )) in the login routine, but 
no go.

Any thoughts on what I might be doing wrong?

Eric