prefetchedAreaRadius

Radius around the current position defining the minimum area for which navigation map data is prefetched and kept available. The actual area fetched can be greater than the requested radius. The larger the radius, the more robust the system is to temporary unavailability of the map data source, but at a greater memory and bandwidth cost. The value must be non-negative integer. The parameter defaults to DEFAULT_RADIUS meters. The maximum value is EARTH_RADIUS_IN_METERS meters.