watch/view.go
func (v *View) DataAndLastIndex() (interface{}, uint64) {
	v.dataLock.RLock()
	defer v.dataLock.RUnlock()
	return v.data, v.lastIndex
}
func (v *View) DataAndLastIndex() (interface{}, uint64) {
	v.dataLock.RLock()
	defer v.dataLock.RUnlock()
	return v.data, v.lastIndex
}
// DataAndLastIndex returns the most-recently-received data from Consul for
// this view, along with the last index. This is atomic so you will get the
// index that goes with the data you are fetching.