(PECL ev >= 0.2.0)
EvLoop::io — Create EvIo watcher object associated with the current event loop instance
$fd
   ,$events
   ,$callback
   ,$data
     = null
   ,$priority
     = 0
   Create EvIo watcher object associated with the current event loop instance.
All parameters have the same meaning as for EvIo::__construct()
Returns EvIo object on success.
