var (
	// WatchExpiryTimeout is the watch expiry timeout for xDS client. It can be
	// overridden by tests to change the default watch expiry timeout.
	WatchExpiryTimeout time.Duration

	// StreamBackoff is the stream backoff for xDS client. It can be overridden
	// by tests to change the default backoff strategy.
	StreamBackoff func(int) time.Duration

	// ResourceWatchStateForTesting gets the watch state for the resource
	// identified by the given resource type and resource name. Returns a
	// non-nil error if there is no such resource being watched.
	ResourceWatchStateForTesting any // func(*xdsclient.XDSClient, xdsclient.ResourceType, string) error
)