Wechat persistence irules!!

1) Local Traffic ›› Profiles : Services : XML : click on Create

to create an XML profile, and specify xpath with "FromUserName";

2) Attach the xml profile to the virtual server;

3) Attach the following irule to the virtual server:

when XML_CONTENT_BASED_ROUTING {
    for {set i 0} { $i < $XML_count } {incr i} {
        log local0. $XML_queries($i)
        log local0. $XML_values($i)
        if {($XML_queries($i) contains "FromUserName")} {
            persist uie $XML_values($i) 0
        }
    }
}
when LB_SELECTED {
    log local0. "Pool member selected: [LB::server addr]"
}

(This is untested.)