Understanding this iRule - to resolve upto 15 seconds lag while playing videos

I need help in understanding the iRule below.

pserver is load balanced server (i.e. pool member which request was sent to).

in short, the irule does http redirection based on load balanced server (i.e. switch statement in HTTP_RESPONSE event).

to resolve upto 15 seconds lag while playing videos

i think packet capture may be more helpful.