// given that memory allocation may trigger GC and block the thread.
	// Also note that emptyFunc is a placeholder, until we will be able
	// to compute watcher.forget function (which has to happen under lock).
	watcher := newCacheWatcher(
		chanSize,
		filterWithAttrsFunction(key, pred),
		emptyFunc,
		c.versioner,
		deadline,
		pred.AllowWatchBookmarks,
		c.groupResource,
		identifier,
	)