Get current default pool name in an iRule?

I went through LB and virtual and I don't see anything that would get the real time configuration of a virtual server.

It looks like most examples are related to setting pool is based on information on the http request (file type, path, etc).

I have a scenario where I want to flip the default pool between a "blue" server pool and a "green" server pool as part of an application deployment. Pooled tcp connections can have long lifetimes which leave them connected to the "off" server pool. I need a way to gracefully route traffic to the new pool without forcing the connection closed.

Is this possible in an iRule?

Something similar to this:

when CLIENT_ACCEPTED {
    set original_pool [LB::server pool]
}

when HTTP_REQUEST {
    pseudo code
    set current_pool [SOME_HOW_GET_THIS_INFO_FROM_THE_VIRTUAL_SERVER]
    if ($current_pool <> $original_pool) {
        pool $current_pool
    }
    pseudo code
}