client connection persistence using an irule

This might give you some ideas.

The iRule will set a persistence record after the pool member has responded.

On subsequent requests (when the variable $clientIp exists) it will persist on the record it has added.

Just be cautious of this method. The client IP could be a NATed IP, so depending on what content you're serving, you could accidentally bleed other user sessions.

when HTTP_REQUEST {
    if {[info exists clientIp]} {
        persist uie $clientIp
    } elseif {[HTTP::header exists "client-ip"]} {
        set clientIp [HTTP::header value "client-ip"]
    }
}
 
when HTTP_RESPONSE {
    if {[info exists clientIp]} {
        persist add uie $clientIp
    }
}

 (this iRule has only been syntax checked)