OptionalbackgroundGeolocation
OptionalselfIf set, the geolocation of the current user will be public for the specified number of seconds; pass 0x7fffffff to disable expiry, 0 to make the current geolocation private; if the flag isn't set, no changes will be applied.
While the geolocation of the current user is public, clients should update it in the background every half-an-hour or so, while setting this flag. Do this only if the new location is more than 1 KM away from the previous one, or if the previous location is unknown.