(PECL ev >= 0.2.0)
EvWatcher is a base class for all watchers( EvCheck , EvChild etc.). Since EvWatcher 's constructor is abstract , one can't(and don't need to) create EvWatcher objects directly.
       Readonly
       . TRUE if the watcher is active. FALSE otherwise.
      
User custom data associated with the watcher
       Readonly
       .TRUE if the watcher is pending, i.e. it has outstanding events, but
       its callback has not yet been invoked. FALSE otherwise. As long, as a
       watcher is pending(but not active), one must
       not
       change its priority.
      
       Integer
       between
       Ev::MINPRI
       and
       Ev::MAXPRI
       . Pending watchers with higher priority will be invoked before watchers
       with lower priority, but priority will not keep watchers from being
       executed(except for
       EvIdle
       watchers).
       EvIdle
       watchers provide functionality to suppress invocation when higher
       priority events are pending.