func (w *commonWatcher) init() {
	w.in = make(chan interface{})
	if w.newResult == nil {
		panic("newResult must be set")
	}
	if w.call == nil {
		panic("call must be set")
	}
}
// init must be called to initialize an embedded commonWatcher's
// fields. Make sure newResult and call fields are set beforehand.
init must be called to initialize an embedded commonWatcher's
fields. Make sure newResult and call fields are set beforehand.
// init must be called to initialize an embedded commonWatcher ' s // fields . Make sure newResult and call fields are set beforehand .
func (w *commonWatcher) init() {
	w.in = make(chan interface{})
	if w.newResult == nil {
		panic("newResult must be set")
	}
	if w.call == nil {
		panic("call must be set")
	}
}
func ( w * commonWatcher ) init ( ) { w . in = make ( chan interface { } ) if w . newResult == nil { panic ( " " ) } if w . call == nil { panic ( " " ) } }
init must be called to initialize an embedded commonWatcher's
fields.
init must be called to initialize an embedded commonWatcher ' s fields .