Flag for MediaRouter.AddCallback(MediaRouteType, .Callback): Actively scan for routes while this callback is registered.

When this flag is specified, the media router will actively scan for new routes. Certain routes, such as wifi display routes, may not be discoverable except when actively scanning. This flag is typically used when the route picker dialog has been opened by the user to ensure that the route information is up to date.

Active scanning may consume a significant amount of power and may have intrusive effects on wireless connectivity. Therefore it is important that active scanning only be requested when it is actually needed to satisfy a user request to discover and select a new route.

[Android Documentation]