src/server/pkg/collection/collection.go
func (c *readonlyCollection) WatchOne(key string) (watch.Watcher, error) {
	return watch.NewWatcher(c.ctx, c.etcdClient, c.prefix, c.Path(key), c.template)
}
func (c *readonlyCollection) WatchOne(key string) (watch.Watcher, error) {
	return watch.NewWatcher(c.ctx, c.etcdClient, c.prefix, c.Path(key), c.template)
}
// WatchOne watches a given item.  The first value returned from the watch
// will be the current value of the item.