`(String a, String b) `tracefile on
The outer most content is cached for 20 seconds, using the CacheFor annotation. ${new Date()}
this part is never cached: `invoke controllers.more.Portlets.panel1("\"never cached\"")`
this part is cached for 10 seconds. Note the timeout spec with invoke overrides CacheFor annotation. `a controllers.more.Portlets.panel2(b), "10s"
this part is cached for 4 seconds, specified with CacheFor annotation in the controller. `a controllers.more.Portlets.panel3(a + b)