Change User on a pconnect

I just added mysql_change_user() to the PHP 3 tree, mostly because someone asked me for it. However, the idea behind the function, and why it was added to MySQL recently was to allow us to maintain a pconnect across different user mysql user ids. This would mean that if we are talking to MySQL-3.23.3 or higher, we would not store the username and password in the hashed_details, but instead just do a change_user. However, I don't want to slow down the pconnect process here with a change_user call that might not be needed. So perhaps we should still store the username/password in hashed_details and let pconnect work the way it has always worked, but have a different puserconnect function or something like that which would do an automatic change_user on a persistent connection and if it fails to authenticate it would not return the connection link identifier to prevent someone from hijacking somebody else's persistent link. Comments? -Rasmus